Language：English   Publishing type：Research paper (scientific journal)  

Androgens play a vital role not only in promoting the development of male sexual characteristics but also in exerting diverse physiological effects, including the regulation of skeletal muscle growth and function. Given that the effects of androgens are mediated through androgen receptor (AR) binding, an understanding of AR functionality is crucial for comprehending the mechanisms of androgen action on skeletal muscles. Drawing from insights gained using conditional knockout mouse models facilitated by Cre/loxP technology, we review the cell-specific functions of AR in skeletal muscles. We focus on three specific cell populations expressing AR within skeletal muscles: skeletal muscle cells, responsible for muscle contraction; satellite cells, which are essential stem cells contributing to the growth and regeneration of skeletal muscles; and mesenchymal progenitors, situated in interstitial areas and playing a crucial role in muscle homeostasis. Furthermore, the indirect effects of androgens on skeletal muscle through extra-muscle tissue are essential, especially for the regulation of skeletal muscle mass. The regulation of genes by AR varies across different cell types and contexts, including homeostasis, regeneration and hypertrophy of skeletal muscles. The varied mechanisms orchestrated by AR collectively influence the physiology of skeletal muscles.

DOI： 10.1507/endocrj.EJ23-0691

PubMed

researchmap

Language：English   Publisher：Cold Spring Harbor Laboratory  

Androgens exert their effects primarily by binding to the androgen receptor (AR), a ligand-dependent nuclear receptor. While androgens have anabolic effects on skeletal muscle, previous studies reported that AR functions in myofibers to regulate skeletal muscle quality, rather than skeletal muscle mass. Therefore, the anabolic effects of androgens are exerted via extra-myofiber cells or tissues. In this context, the cellular and molecular mechanisms of AR in mesenchymal progenitors, which play a crucial role in maintaining skeletal muscle homeostasis, remain largely unknown. In this study, we demonstrated expression of AR in mesenchymal progenitors and found that targeted AR ablation in mesenchymal progenitors reduced limb muscle mass in mature adult, but not young or aged, male mice, although fatty infiltration of muscle was not affected. The absence of AR in mesenchymal progenitors led to remarkable perineal muscle hypotrophy, regardless of age, due to abnormal regulation of transcripts associated with apoptosis and proteolysis. Additionally, we revealed that AR in mesenchymal progenitors regulates the expression of insulin-like growth factor 1, which can increase skeletal muscle mass in a paracrine manner. These findings indicate that the anabolic effects of androgens indirectly regulate skeletal muscle mass via, at least in part, AR signaling in mesenchymal progenitors.

DOI： 10.1101/2023.11.21.568190

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s00774-024-01506-6

PubMed

researchmap

Other Link： https://link.springer.com/article/10.1007/s00774-024-01506-6/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.cyto.2024.156506

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

Rheumatoid arthritis (RA) is an inflammatory autoimmune disease characterized by synovitis, bone and cartilage destruction, and increased fracture risk with bone loss. Although disease–modifying antirheumatic drugs have dramatically improved clinical outcomes, these therapies are not universally effective in all patients because of the heterogeneity of RA pathogenesis. Therefore, it is necessary to elucidate the molecular mechanisms underlying RA pathogenesis, including associated bone loss, in order to identify novel therapeutic targets. In this study, we found that Budding uninhibited by benzimidazoles 1 (BUB1) was highly expressed in RA patients’ synovium and murine ankle tissue with arthritis. As CD45+CD11b+ myeloid cells are a Bub1 highly expressing population among synovial cells in mice, myeloid cell–specific Bub1 conditional knockout (Bub1ΔLysM) mice were generated. Bub1ΔLysM mice exhibited reduced femoral bone mineral density when compared with control (Ctrl) mice under K/BxN serum–transfer arthritis, with no significant differences in joint inflammation or bone erosion based on a semi–quantitative erosion score and histological analysis. Bone histomorphometry revealed that femoral bone mass of Bub1ΔLysM under arthritis was reduced by increased osteoclastic bone resorption. RNA-seq and subsequent Gene Set Enrichment Analysis demonstrated a significantly enriched nuclear factor-kappa B pathway among upregulated genes in receptor activator of nuclear factor kappa B ligand (RANKL)–stimulated bone marrow–derived macrophages (BMMs) obtained from Bub1ΔLysM mice. Indeed, osteoclastogenesis using BMMs derived from Bub1ΔLysM was enhanced by RANKL and tumor necrosis factor-α or RANKL and IL-1β treatment compared with Ctrl. Finally, osteoclastogenesis was increased by Bub1 inhibitor BAY1816032 treatment in BMMs derived from wildtype mice. These data suggest that Bub1 expressed in macrophages plays a protective role against inflammatory arthritis–associated bone loss through inhibition of inflammation–mediated osteoclastogenesis.

DOI： 10.1093/jbmr/zjae015

PubMed

researchmap

Other Link： https://academic.oup.com/jbmr/article-pdf/39/3/341/57285020/zjae015.pdf

Publishing type：Research paper (scientific journal)   Publisher：Japan Endocrine Society  

DOI： 10.1507/endocrj.ej23-0691

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Osteophyte formation is attracting attention as an early-stage pathology of knee osteoarthritis (OA). Although osteophyte formation is understood as a defense response to joint instability, its role and impact on OA remain largely unknown. Many studies have been conducted using the surgical destabilization of the medial meniscus (DMM) mouse model, but there are few standard evaluation methods, especially in the histological evaluation of early-stage osteophytes. The purpose of this study was to establish a reproducible and uniform method for histological evaluation of characteristics of early osteophyte formation in the DMM mouse model. METHODS: Male mice were operated with DMM at 12 weeks old and histologically evaluated at 4 days and 1, 2 and 4 weeks after DMM. Osteophyte Width, Osteophyte Area, and Original and Modified Maturity Scores were used to evaluate osteophytes for all sections. RESULTS: Osteophyte Width, Osteophyte Area and Maturity Scores were all greater anteriorly than posteriorly in the knee joint. The Modified Maturity Score was more strongly correlated with position than the Original Maturity Score, and could be used to evaluate early-stage osteophyte formation. CONCLUSION: The Modified Maturity Score as well as Osteophyte Width and Area at the section of the anterior cruciate ligament (ACL) attachment site can provide a reproducible evaluation method to histologically assess the early-stage osteophyte formation in the DMM mouse model.

DOI： 10.1016/j.ocarto.2023.100409

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Osteoclasts uniquely resorb calcified bone matrices. To exert their function, mature osteoclasts maintain the cellular polarity and directional vesicle trafficking to and from the resorbing bone surface. However, the regulatory mechanisms and pathophysiological relevance of these processes remain largely unexplored. Bone histomorphometric analyses in Ccr5-deficient mice showed abnormalities in the morphology and functional phenotype of their osteoclasts, compared to wild type mice. We observed disorganized clustering of nuclei, as well as centrosomes that organize the microtubule network, which was concomitant with impaired cathepsin K secretion in cultured Ccr5-deficient osteoclasts. Intriguingly, forced expression of constitutively active Rho or Rac restored these cytoskeletal phenotypes with recovery of cathepsin K secretion. Furthermore, a gene-disease enrichment analysis identified that PLEKHM1, a responsible gene for osteopetrosis, which regulates lysosomal trafficking in osteoclasts, was regulated by CCR5. These experimental results highlighted that CCR5-mediated signaling served as an intracellular organizer for centrosome clustering in osteoclasts, which was involved in the pathophysiology of bone metabolism.

DOI： 10.1038/s41598-023-48140-2

researchmap

Other Link： https://www.nature.com/articles/s41598-023-48140-2

Publisher：Cold Spring Harbor Laboratory  

Summary

Transcribed cis-regulatory elements (tCREs), such as promoters and enhancers, are fundamental to modulate gene expression and define cell identity. The detailed mapping of tCREs at single-cell resolution is essential for understanding the regulatory mechanisms that govern cellular functions. Prior tCRE catalogs, limited by bulk analysis, have often overlooked cellular heterogeneity. We have constructed a tCRE atlas using single-cell 5’-RNA-seq, capturing over 340,000 single-cells from 23 human tissues and annotating more than 175,000 tCREs, substantially enhancing the scope and granularity of existingcis-regulatory element annotations in the human genome. This atlas unveils patterns of gene regulation, revealing connections between broadly expressed promoters and cell type-specific distal tCREs. Assessing trait heritability at single-cell resolution with a novel tCRE module-based approach, we uncovered the nuanced trait-gene regulatory relationships across a continuum of cell populations, offering insights beyond traditional gene-level and bulk-sample analyses. Our study bridges the gap between gene regulation and trait heritability, underscoring the potential of single-cell analysis to elucidate the genetic foundations of complex traits. These insights set the stage for future research to investigate the impact of genetic variations on diseases at the individual level, advancing the understanding of cellular and molecular basis of trait heritability.

DOI： 10.1101/2023.11.13.566791

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Rheumatoid arthritis (RA) is an autoimmune disease associated with chronic inflammation of joints. Abnormally activated cells such as synovial macrophages and synovial fibroblasts induce RA pathogenesis and ultimately joint destruction. Since macrophages can change their own characteristics depending on the microenvironmental condition, it has been suggested that activation and remission of RA are regulated by crosstalk between synovial macrophages and other cells. Moreover, recent findings of heterogeneity of synovial macrophages and fibroblasts support the idea that complex interactions regulate RA from its onset to remission. Importantly, an understanding of the intercellular crosstalk in RA is far from complete. Here, we summarize the molecular mechanisms underlying the pathological development of RA with particular reference to the crosstalk between synovial macrophages and fibroblasts.

DOI： 10.14670/HH-18-628

PubMed

researchmap

Language：English   Publisher：(一社)西日本泌尿器科学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Lenalidomide, an immunomodulatory drug (IMiD), is commonly used as a first-line therapy in many haematological cancers, such as multiple myeloma (MM) and 5q myelodysplastic syndromes (5q MDS), and it functions as a molecular glue for the protein degradation of neosubstrates by CRL4CRBN. Proteolysis-targeting chimeras (PROTACs) using IMiDs with a target protein binder also induce the degradation of target proteins. The targeted protein degradation (TPD) of neosubstrates is crucial for IMiD therapy. However, current IMiDs and IMiD-based PROTACs also break down neosubstrates involved in embryonic development and disease progression. Here, we show that 6-position modifications of lenalidomide are essential for controlling neosubstrate selectivity; 6-fluoro lenalidomide induced the selective degradation of IKZF1, IKZF3, and CK1α, which are involved in anti-haematological cancer activity, and showed stronger anti-proliferative effects on MM and 5q MDS cell lines than lenalidomide. PROTACs using these lenalidomide derivatives for BET proteins induce the selective degradation of BET proteins with the same neosubstrate selectivity. PROTACs also exert anti-proliferative effects in all examined cell lines. Thus, 6-position-modified lenalidomide is a key molecule for selective TPD using thalidomide derivatives and PROTACs.

DOI： 10.1038/s41467-023-40385-9

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

ABSTRACT

In this randomized, double-blind, placebo-controlled study, we investigated the effects of collagen peptides (CP) containing high concentrations of prolyl-hydroxyproline and hydroxyprolyl-glycine on advanced glycation end products (AGEs) levels in the skin and subcutaneous blood vessel walls. A total of 31 individuals aged 47-87 years were randomly assigned to receive either 5 g/day of fish-derived CP or a placebo for 12 weeks. Body and blood compositions and AGEs levels were measured at the beginning and end of the study. No adverse events were observed, and both groups’ blood and body compositions did not change significantly. However, the CP group had significantly lower AGEs levels and a slightly lower insulin resistance index (homeostasis model assessment ratio [HOMA-R]) than the placebo group. In addition, the percentage changes in AGEs and HOMA-R levels were positively and strongly correlated in both groups. These findings suggest that fish-derived CP may be effective in reducing AGEs levels and improving insulin resistance.

DOI： 10.1093/bbb/zbad065

PubMed

researchmap

Other Link： https://academic.oup.com/bbb/article-pdf/87/8/883/50951769/zbad065.pdf

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Frontiers Media SA  

Introduction

The incidence of endometrial cancer (EC) has been increasing worldwide. However, because there are limited chemotherapeutic options for the treatment of EC, the prognosis of advanced-stage EC is poor.

Methods

Gene expression profile datasets for EC cases registered in The Cancer Genome Atlas (TCGA) was reanalyzed. Highly expressed genes in advanced-stage EC (110 cases) compared with early-stage EC (255 cases) were extracted and Gene Ontology (GO) enrichment analysis was performed. Among the enriched genes, Kaplan-Meier (KM) plotter analysis was performed. Candidate genes expression was analyzed in HEC50B cells and Ishikawa cells by RT-qPCR. In HEC50B cells, LIM homeobox1 (LIM1) was knocked down (KD) and cell proliferation, migration, and invasion ability of the cells were evaluated. Xenografts were generated using LIM1-KD cells and tumor growth was evaluated. Ingenuity Pathway Analysis (IPA) of RNA-seq data using LIM-KD cells was performed. Expression of phospho-CREB and CREB-related proteins were evaluated in LIM1-KD cells by western blotting and in xenograft tissue by immunofluorescent staining. Two different CREB inhibitors were treated in HEC50B and cell proliferation was evaluated by MTT assay.

Results

Reanalysis of TCGA followed by GO enrichment analysis revealed that homeobox genes were highly expressed in advanced-stage EC. Among the identified genes, KM plotter analysis showed that high LIM1 expression was associated with a significantly poorer prognosis in EC. Additionally, LIM1 expression was significantly higher in high-grade EC cell lines, HEC50B cells than Ishikawa cells. Knockdown of LIM1 showed reduced cell proliferation, migration and invasion in HEC50B cells. Xenograft experiments revealed that tumor growth was significantly suppressed in LIM1-KD cells. IPA of RNA-seq data using LIM-KD cells predicted that the mRNA expression of CREB signaling-related genes was suppressed. Indeed, phosphorylation of CREB was decreased in LIM1-KD cells and LIM1-KD cells derived tumors. HEC50B cells treated by CREB inhibitors showed suppression of cell proliferation.

Conclusion and discussion

Collectively, these results suggested that high LIM1 expression contributed to tumor growth via CREB signaling in EC. Inhibition of LIM1 or its downstream molecules would be new therapeutic strategies for EC.

DOI： 10.3389/fonc.2023.1082441

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MyJove Corporation  

DOI： 10.3791/65196

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Ligamentum flavum (LF) hypertrophy is a major cause of lumbar spinal canal stenosis. Although mechanical stress is thought to be a major factor involved in LF hypertrophy, the exact mechanism by which it causes hypertrophy has not yet been fully elucidated. Here, changes in gene expression due to long-term mechanical stress were analyzed using RNA-seq in a rabbit LF hypertrophy model. In combination with previously reported analysis results, periostin was identified as a molecule whose expression fluctuates due to mechanical stress. The expression and function of periostin were further investigated using human LF tissues and primary LF cell cultures. Periostin was abundantly expressed in human hypertrophied LF tissues, and periostin gene expression was significantly correlated with LF thickness. In vitro, mechanical stress increased gene expressions of periostin, transforming growth factor-β1, α-smooth muscle actin, collagen type 1 alpha 1, and interleukin-6 (IL-6) in LF cells. Periostin blockade suppressed the mechanical stress-induced gene expression of IL-6 while periostin treatment increased IL-6 gene expression. Our results suggest that periostin is upregulated by mechanical stress and promotes inflammation by upregulating IL-6 expression, which leads to LF degeneration and hypertrophy. Periostin may be a pivotal molecule for LF hypertrophy and a promising therapeutic target for lumbar spinal stenosis.

DOI： 10.1096/fj.202200917RR

PubMed

researchmap

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Benign paroxysmal positional vertigo (BPPV) is associated with menopause and/or osteopenia. Morphological changes in the otoconial layer have been reported after ovariectomy (OVX). Moreover, hormone replacement therapy decreases BPPV risk. However, knowledge concerning the effect of hormonal therapy on the otoconial changes caused by estrogen deficiency is limited. We aimed to examine the effect of hormonal therapy on otoconial changes caused by estrogen deficiency. We hypothesized that hormonal therapy could reduce otoconial changes caused by OVX. Eight-week-old C57BL/6 mice were divided into four groups: sham operation with implantation of vehicle (sham + v), OVX with implantation of vehicle (OVX + v), OVX with implantation of estradiol (E2) (OVX + E2), and OVX with implantation of raloxifene (RAL) (OVX + RAL) groups. Otoconial layer volume was measured by micro-CT at 4 weeks after OVX or the sham operation. The otic bullae were removed; immunohistochemistry was performed for estrogen receptor alpha and 4-hydroxynonenal. Otoconial layer volume was significantly higher in the OVX + v than in the sham + v group. E2 and RAL significantly reduced these changes in the endometrial layer. The staining of estrogen receptor alpha and 4-hydroxynonenal were stronger in the OVX + v than in the sham + v group but equal in the sham + v, OVX + E2, and OVX + RAL groups. These results indicate that E2 and RAL are effective against morphological changes of the otoconial layer caused by estrogen deficiency via oxidative stress reduction.

DOI： 10.1038/s41598-022-27240-5

researchmap

Other Link： https://www.nature.com/articles/s41598-022-27240-5

Language：English   Publishing type：Research paper (scientific journal)  

INTRODUCTION: Osteoblasts require substantial amounts of energy to synthesize the bone matrix and coordinate skeleton mineralization. This study analyzed the effects of mitochondrial dysfunction on bone formation, nano-organization of collagen and apatite, and the resultant mechanical function in mouse limbs. MATERIALS AND METHODS: Limb mesenchyme-specific Tfam knockout (Tfamf/f;Prx1-Cre: Tfam-cKO) mice were analyzed morphologically and histologically, and gene expressions in the limb bones were assessed by in situ hybridization, qPCR, and RNA sequencing (RNA-seq). Moreover, we analyzed the mitochondrial function of osteoblasts in Tfam-cKO mice using mitochondrial membrane potential assay and transmission electron microscopy (TEM). We investigated the pathogenesis of spontaneous bone fractures using immunohistochemical analysis, TEM, birefringence analyzer, microbeam X-ray diffractometer and nanoindentation. RESULTS: Forelimbs in Tfam-cKO mice were significantly shortened from birth, and spontaneous fractures occurred after birth, resulting in severe limb deformities. Histological and RNA-seq analyses showed that bone hypoplasia with a decrease in matrix mineralization was apparent, and the expression of type I collagen and osteocalcin was decreased in osteoblasts of Tfam-cKO mice, although Runx2 expression was unchanged. Decreased type I collagen deposition and mineralization in the matrix of limb bones in Tfam-cKO mice were associated with marked mitochondrial dysfunction. Tfam-cKO mice bone showed a significantly lower Young's modulus and hardness due to poor apatite orientation which is resulted from decreased osteocalcin expression. CONCLUSION: Mice with limb mesenchyme-specific Tfam deletions exhibited spontaneous limb bone fractures, resulting in severe limb deformities. Bone fragility was caused by poor apatite orientation owing to impaired osteoblast differentiation and maturation.

DOI： 10.1007/s00774-022-01354-2

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Developmental dysplasia of the hip (DDH) is characterized by anatomical abnormalities of the hip joint, ranging from mild acetabular dysplasia to hip subluxation and eventually dislocation. The mechanism underlying the cartilage degeneration of the hip joints exposed to reduced dynamic loads due to hip dislocation remains unknown. We established a rodent hip dislocation (disarticulation; DA) model of DDH (DA-DDH rats and mice) by swaddling. Expression levels of periostin (Postn) and catabolic factors, such as interleukin-6 (IL-6) and matrix metalloproteinase 3 (Mmp3), increased and those of chondrogenic markers decreased in the acetabular cartilage of the DA-DDH models. Postn induced IL-6 and Mmp3 expression in chondrocytes through integrin αVβ3, focal adhesion kinase, Src, and nuclear factor-κB (NF-κB) signaling. The microgravity environment created by a random positioning machine induced Postn expression in chondrocytes through signal transducer and activator of transcription 3 (STAT3) signaling. IL-6 stimulated Postn expression via STAT3 signaling. Furthermore, cartilage degeneration was suppressed in the acetabulum of Postn^−/− DA-DDH mice compared with that in the acetabulum of wild type DA-DDH mice. In summary, reduced dynamic loads due to hip dislocation induced acetabular cartilage degeneration via IL-6 and MMP3 through STAT3/periostin/NF-κB signaling in the rodent DA-DDH models.

DOI： 10.1038/s41598-022-16585-6

researchmap

Other Link： https://www.nature.com/articles/s41598-022-16585-6

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Abstract

Background

Lubricin, a proteoglycan encoded by the PRG4 gene, is synthesised by superficial zone (SFZ) chondrocytes and synovial cells. It reduces friction between joints and allows smooth sliding of tendons. Although lubricin has been shown to be effective against osteoarthritis and synovitis in animals, its clinical application remains untested. In this study, we aimed to induce lubricin-expressing cells from pluripotent stem cells (iPSCs) and applied them locally via cell transplantation.

Methods

To generate iPSCs, OCT3/4, SOX2, KLF4, and L-MYC were transduced into fibroblasts derived from Prg4-mRFP1 transgenic mice. We established a protocol for the differentiation of iPSC-derived Prg4-mRFP1-positive cells and characterised their mRNA expression profile. Finally, we injected Prg4-mRFP1-positive cells into the paratenon, surrounding the Achilles tendons and knee joints of severe combined immunodeficient mice and assessed lubricin expression.

Result

Wnt3a, activin A, TGF-β1, and bFGF were applied to induce the differentiation of iPSC-derived Prg4-mRFP1-positive cells. Markers related to SFZ chondrocytes and fibroblast-like synovial cells (FLSs) were expressed during differentiation. RNA-sequencing indicated that iPSC-derived Prg4-mRFP1-positive cells manifested expression profiles typical of SFZ chondrocytes and FLSs. Transplanted iPSC-derived Prg4-mRFP1-positive cells survived around the Achilles tendons and in knee joints.

Conclusions

The present study describes a protocol for the differentiation of iPSC-derived Prg4-positive cells with characteristics of SFZ chondrocytes and FLSs. Transplantation of lubricin-expressing cells offers promise as a therapy against arthritis and synovitis.

DOI： 10.1186/s12860-022-00431-8

Scopus

PubMed

researchmap

Other Link： https://link.springer.com/article/10.1186/s12860-022-00431-8/fulltext.html

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Society for Clinical Investigation  

Rheumatoid arthritis (RA) is characterized by chronic synovial inflammation with aberrant epigenetic alterations, eventually leading to joint destruction. However, the epigenetic regulatory mechanisms underlying RA pathogenesis remain largely unknown. Here, we showed that ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) is a central epigenetic regulator that orchestrates multiple pathogeneses in RA in a suppressive manner. UHRF1 expression was remarkably upregulated in synovial fibroblasts (SFs) from arthritis model mice and patients with RA. Mice with SF-specific Uhrf1 conditional knockout showed more severe arthritic phenotypes than littermate controls. Uhrf1-deficient SFs also exhibited enhanced apoptosis resistance and upregulated expression of several cytokines, including Ccl20. In patients with RA, DAS28, CRP, and Th17 accumulation and apoptosis resistance were negatively correlated with UHRF1 expression in synovium. Finally, Ryuvidine administration stabilized UHRF1 ameliorated arthritis pathogeneses in a mouse model of RA. This study demonstrated that UHRF1 expressed in RA SFs can contribute to negative feedback mechanisms that suppress multiple pathogenic events in arthritis, suggesting that targeting UHRF1 could be one of the therapeutic strategies for RA.

DOI： 10.1172/JCI150533

PubMed

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DNA methylation is an essential form of epigenetic regulation responsible for cellular identity. In muscle stem cells, termed satellite cells, DNA methylation patterns are tightly regulated during differentiation. However, it is unclear how these DNA methylation patterns affect the function of satellite cells. We demonstrate that a key epigenetic regulator, ubiquitin like with PHD and RING finger domains 1 (Uhrf1), is activated in proliferating myogenic cells but not expressed in quiescent satellite cells or differentiated myogenic cells in mice. Ablation of Uhrf1 in mouse satellite cells impairs their proliferation and differentiation, leading to failed muscle regeneration. Uhrf1-deficient myogenic cells exhibited aberrant upregulation of transcripts, including Sox9, with the reduction of DNA methylation level of their promoter and enhancer region. These findings show that Uhrf1 is a critical epigenetic regulator of proliferation and differentiation in satellite cells, by controlling cell-type-specific gene expression via maintenance of DNA methylation.

DOI： 10.1016/j.isci.2022.103928

PubMed

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Osteocytes are master regulators of skeletal homeostasis. However, little is known about the molecular mechanism of their differentiation. Epigenetic regulations, especially H3K27me3 modification, play critical roles in cell differentiation. Here, we found that H3K27me3 in the loci of osteocyte-expressing genes decreased during osteocyte differentiation and that H3K27me3 demethylase, Utx, was bound to the loci of those genes. To investigate the physiological functions of Utx in vivo, we generated late osteoblast-to-osteocyte specific Utx knockout mice using Dmp1-cre mice (UtxΔOcy/ΔOcy). Micro CT analyses showed that UtxΔOcy/ΔOcy displayed osteopenic phenotypes with lower bone volume and trabecular number, and greater trabecular separation. Bone histomorphometric analysis showed that bone mineralization and formation were significantly lower in UtxΔOcy/ΔOcy. Furthermore, Dmp1 expression and the number of osteocytes were significantly decreased in UtxΔOcy/ΔOcy. These results suggest that Utx in Dmp1-expressing osteoblast/osteocyte positively regulates osteoblast-to-osteocyte differentiation through H3K27me3 modifications in osteocyte genes. Our results provide new insight into the molecular mechanism of osteocyte differentiation.

DOI： 10.1016/j.bbrc.2021.12.102

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Pericytes are pluripotent cells that enclose the endothelium of small blood vessels in the whole body. These cells are thought to play a limited role in vascular development and blood pressure regulation; however, current evidence from numerous studies suggests several significant biologic aspects of pericytes in animals. One viewpoint is that pericytes are also known as potential cellular origin of multiple soft tissue tumors. Experimental evidence of the cellular origin of pericytic tumors is still insufficient, however, and their molecular pathogenesis is poorly understood. Here, we used a conditional constitutively active Smoothened allele (Rosa-SmoM2) and Cre recombinase mice to activate hedgehog (Hh) signaling, exclusively in the monocyte/macrophage and osteoclast lineage (LysMcre) or in RANK expressing cells (RANKcre) that are recognized as osteoclast precursor cells. Mice conditionally expressing SmoM2 with LysMcre displayed no significant skeletal phenotype; surprisingly, however, RANKcre; Rosa-SmoM2 mice frequently developed progressive soft tissue tumors in regions of the leg. Genetic lineage tracing analysis uncovered a new domain of RANKcre-expressing cells in the skeletal muscle interstitial cells that display markers consistent with vascular pericytes. Neoplasms arising from these cells showed increased expression of Matrix metalloproteinases (MMPs) that are molecular indicators of malignancy. Moreover, the tumors displayed strong bone invasive potency associated with osteoclastic bone resorption. Thus, these findings provide a novel insight into tumor pathology: Hh signal activated-pericytes can be a potential cellular origin of multiple soft tissue tumors.

DOI： 10.1007/s00441-022-03578-0

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Macrophages are progenitors of osteoclasts as well as regulators of bone metabolism. Macrophages mediate not only bone formation by osteoblasts under physiological conditions, but also bone regeneration after fracture. The mechanisms of macrophages regulation of bone formation and regeneration remain unclear, however. Here, we demonstrate that the liposome-encapsulated Clodronate (Clod-lip) injected mouse model with cortical bone defect induced by drill-hole injury and targeted depletion of phagocytic macrophages exhibits impaired angiogenesis of type H vessels that couple angiogenesis and osteogenesis. Moreover, we identify Tgfbi (encoding TGFBI), Plau (encoding uPA) and Tgfb1 (encoding TGF-β1), through RNA-seq analysis, as genes of macrophage-secreted factors mediating angiogenesis and wound healing. The relevant mRNA was highly expressed in bone marrow-derived macrophages among bone cells, as determined through qRT-PCR. Finally, we disclose that treatment with uPA inhibitor or TGF-β receptor I, receptor II inhibitor impairs bone regeneration after injury, confirming the importance of uPA and TGF-β1 during bone regeneration. Our findings reveal a novel mechanism of bone regeneration mediated by macrophages.

DOI： 10.1016/j.bone.2021.116200

PubMed

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：日本組織細胞化学会  

researchmap

Language：Japanese   Publisher：日本組織細胞化学会  

researchmap

Language：Japanese   Publisher：日本組織細胞化学会  

researchmap

Language：Japanese   Publisher：日本組織細胞化学会  

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Estrogen deficiency impairs fracture healing and homeostasis of bone tissue. OVX-induced estrogen deficiency in mice attenuates fracture healing and changes the expression ratio of estrogen receptor (ER) α and ERβ in callus during the process of fracture healing. Therefore, ERs may be involved in the regulation of fracture healing. However, the roles of ERs in fracture healing are largely unknown. The purpose of this study was to clarify the significance of ERs during fracture healing using osteoblast-specific ER knockout mice in a mono-cortical drill hole bone regeneration model. The mature osteoblast-specific ER knockout mice were generated using osteocalcin (OCN)-Cre mice, and ERα and ERβ flox mice (OCN-Cre; ERαf/f, ERαΔOb/ΔOb and OCN-Cre; ERβf/f, ERβΔOb/ΔOb). Drill hole surgery was conducted on the tibiae of 8-week-old female mice. The mice were sacrificed 10 or 14 days after surgery and the bones were analyzed by DXA, μCT and bone histomorphometry. DXA analysis revealed that intact femoral BMD was significantly decreased in ERαΔOb/ΔOb mice compared with ERαf/f mice, but there was no difference in bone mass between ERβΔOb/ΔOb and ERβf/f mice. Micro CT analyses showed that the callus volume at the restricted drill hole site in tibiae was significantly less in ERαΔOb/ΔOb compared to ERαf/f mice only at day 14 but not at day 10. In addition to femoral BMD, there was no significant difference in callus volume between ERβΔOb/ΔOb and ERβf/f mice. Bone histomorphometric analyses showed that Ob.S/BS and N.Ob/B.Pm were significantly less in ERαΔOb/ΔOb mice compared with ERαf/f mice only at day 10. In addition, Oc.S/BS and N.Oc/B.Pm were significantly less in ERαΔOb/ΔOb mice compared with ERαf/f mice only at day 14. These results suggest that ERα but not ERβ in osteocalcin-positive osteoblasts may contribute to the late stage of bone regeneration.

DOI： 10.1016/j.bbrc.2021.04.112

PubMed

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.isci.2021.102303

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Bone morphogenetic proteins (BMPs) induce osteogenesis in various environments. However, when BMPs are used alone in the bone marrow environment, the maintenance of new bone formation is difficult owing to vigorous bone resorption. This is because BMPs stimulate the differentiation of not only osteoblast precursor cells but also osteoclast precursor cells. The present study aimed to induce and maintain new bone formation using the topical co-administration of recombinant human BMP-2 (rh-BMP-2) and zoledronate (ZOL) on beta-tricalcium phosphate (β-TCP) composite. METHODS: β-TCP columns were impregnated with both rh-BMP-2 (30 µg) and ZOL (5 µg), rh-BMP-2 alone, or ZOL alone, and implanted into the left femur canal of New Zealand white rabbits (n = 56). The implanted β-TCP columns were harvested and evaluated at 3 and 6 weeks after implantation. These harvested β-TCP columns were evaluated radiologically using plane radiograph, and histologically using haematoxylin/eosin (H&E) and Masson's trichrome (MT) staining. In addition, micro-computed tomography (CT) was performed for qualitative analysis of bone formation in each group (n = 7). RESULTS: Tissue sections stained with H&E and MT dyes revealed that new bone formation inside the β-TCP composite was significantly greater in those impregnated with both rh-BMP-2 and ZOL than in those from the other experimental groups at 3 and 6 weeks after implantations (p < 0.05). Micro-CT data also demonstrated that the bone volume and the bone mineral density inside the β-TCP columns were significantly greater in those impregnated with both rh-BMP-2 and ZOL than in those from the other experimental groups at 3 and 6 weeks after implantations (p < 0.05). CONCLUSIONS: The topical co-administration of both rh-BMP-2 and ZOL on β-TCP composite promoted and maintained newly formed bone structure in the bone marrow environment.

DOI： 10.1186/s12891-021-03971-w

PubMed

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Epigenetic transcriptional regulation is essential for the differentiation of various types of cells, including skeletal muscle cells. DNA methyltransferase 1 (Dnmt1) is responsible for maintenance of DNA methylation patterns via cell division. Here, we investigated the relationship between Dnmt1 and skeletal muscle regeneration. We found that Dnmt1 is upregulated in muscles during regeneration. To assess the role of Dnmt1 in satellite cells during regeneration, we performed conditional knockout (cKO) of Dnmt1 specifically in skeletal muscle satellite cells using Pax7CreERT2 mice and Dnmt1 flox mice. Muscle weight and the cross-sectional area after injury were significantly lower in Dnmt1 cKO mice than in control mice. RNA sequencing analysis revealed upregulation of genes involved in cell adhesion and apoptosis in satellite cells from cKO mice. Moreover, satellite cells cultured from cKO mice exhibited a reduced number of cells. These results suggest that Dnmt1 is an essential factor for muscle regeneration and is involved in positive regulation of satellite cell number.

DOI： 10.1016/j.bbrc.2020.11.116

PubMed

researchmap

Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

DOI： 10.1002/rco2.28

researchmap

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/rco2.28

Language：Japanese   Publisher：(一社)日本泌尿器科学会総会事務局  

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

<title>Abstract</title><sec>
<title>Background</title>
Macrophages adapt to microenvironments, and change metabolic status and functions to regulate inflammation and/or maintain homeostasis. In joint cavities, synovial macrophages (SM) and synovial fibroblasts (SF) maintain homeostasis. However, under inflammatory conditions such as rheumatoid arthritis (RA), crosstalk between SM and SF remains largely unclear.


</sec><sec>
<title>Methods</title>
Immunofluorescent staining was performed to identify localization of SM and SF in synovium of collagen antibody induced arthritis (CAIA) model mice and normal mice. Murine arthritis tissue-derived SM (ADSM), arthritis tissue-derived SF (ADSF) and normal tissue-derived SF (NDSF) were isolated and the purity of isolated cells was examined by RT-qPCR and flow cytometry analysis. RNA-seq was conducted to reveal gene expression profile in ADSM, NDSF and ADSF. Cellular metabolic status and expression levels of metabolic genes and inflammatory genes were analyzed in ADSM treated with ADSM-conditioned medium (ADSM-CM), NDSF-CM and ADSF-CM.



</sec><sec>
<title>Results</title>
SM and SF were dispersed in murine hyperplastic synovium. Isolations of ADSM, NDSF and ADSF to analyze the crosstalk were successful with high purity. From gene expression profiles by RNA-seq, we focused on secretory factors in ADSF-CM, which can affect metabolism and inflammatory activity of ADSM. ADSM exposed to ADSF-CM showed significantly upregulated glycolysis and mitochondrial respiration as well as glucose and glutamine uptake relative to ADSM exposed to ADSM-CM and NDSF-CM. Furthermore, mRNA expression levels of metabolic genes, such as <italic>Slc2a1, Slc1a5, CD36</italic>, <italic>Pfkfb1, Pfkfb3</italic> and <italic>Irg1</italic>, were significantly upregulated in ADSM treated with ADSF-CM. Inflammation marker genes, including <italic>Nos2, Tnf, Il-1b</italic> and <italic>CD86</italic>, and the anti-inflammatory marker gene, <italic>Il-10</italic>, were also substantially upregulated by ADSF-CM. On the other hand, NDSF-CM did not affect metabolism and gene expression in ADSM.


</sec><sec>
<title>Conclusions</title>
These findings suggest that crosstalk between SM and SF under inflammatory conditions can induce metabolic reprogramming and extend SM viability that together can contribute to chronic inflammation in RA.



</sec>

DOI： 10.1186/s12964-020-00678-8

researchmap

Other Link： http://link.springer.com/article/10.1186/s12964-020-00678-8/fulltext.html

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

OBJECTIVE: Estrogen deficiency caused by bilateral ovariectomy (OVX) has been reported to lead to morphological changes in otoconia. Thus, we examined the morphological changes in the otoconial layer after OVX. We also investigated whether micro-computed tomography (µCT) is useful for the detection of morphological changes in the otoconial layer. METHODS: The otic capsules of C57BL/6 J mice were removed and evaluated using histological techniques and µCT at 2, 4, and 8 weeks after OVX or sham surgery. The volume of the utricle otoconial layer was measured and compared between the OVX and sham groups. The µCT scan and histological study results were also compared. RESULTS: The volume of the utricle otoconial layer was significantly increased 4 weeks after OVX compared to the sham group in both histological and µCT studies (p < 0.05). The volume of the otoconial layer measured using µCT was significantly correlated with the histological study results (p < 0.05). CONCLUSION: The volume of the utricle otoconial layer increased after OVX. These morphological changes could be detected by µCT.

DOI： 10.1016/j.anl.2020.02.013

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Estrogens are female sex hormones that are important for comprehensively maintaining muscle function, and an insufficiency affects muscle strength and regeneration in females. However, it is still unclear whether estrogen signaling is mediated through receptors. To investigate the specific role of estrogen receptor β (ERβ) in skeletal muscle and satellite cells (muscle stem cells), we generated muscle-specific ERβ-knockout (mKO) and satellite cell-specific ERβ-knockout (scKO) mice, respectively. Young female mKO mice displayed a decrease in fast-type dominant muscle mass. Female, but not male, scKO mice exhibited impaired muscle regeneration following acute muscle injury, probably due to reduced proliferation and increased apoptosis of satellite cells. RNA-sequencing analysis revealed that loss of ERβ in satellite cells altered gene expression of extracellular matrix components, including laminin and collagen. The results indicate that the estrogen-ERβ pathway is a sex-specific regulatory mechanism that controls muscle growth and regeneration in female mice.

DOI： 10.1016/j.stemcr.2020.07.017

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The development of high-throughput genotyping technologies and large biobank collections, complemented with rapid methodological advances in statistical genetics, has enabled hypothesis-free genome-wide association studies (GWAS), which have identified hundreds of genetic variants across many loci associated with musculoskeletal conditions. Similarly, basic scientists have valuable molecular cellular and animal data based on musculoskeletal disease that would be enhanced by being able to determine the human translation of their findings. By integrating these large-scale human genomic musculoskeletal datasets with complementary evidence from model organisms, new and existing genetic loci can be statistically fine-mapped to plausibly causal variants, candidate genes, and biological pathways. Genes and pathways identified using this approach can be further prioritized as drug targets, including side-effect profiling and the potential for new indications. To bring together these big data, and to realize the vision of creating a knowledge portal, the International Federation of Musculoskeletal Research Societies (IFMRS) established a working group to collaborate with scientists from the Broad Institute to create the Musculoskeletal Knowledge Portal (MSK-KP)(http://mskkp.org/). The MSK consolidates omics datasets from humans, cellular experiments, and model organisms into a central repository that can be accessed by researchers. The vision of the MSK-KP is to enable better understanding of the biological mechanisms underlying musculoskeletal disease and apply this knowledge to identify and develop new disease interventions. © 2020 American Society for Bone and Mineral Research (ASBMR).

DOI： 10.1002/jbmr.4147

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The functional role of the Hedgehog (Hh)-signaling pathway has been widely investigated in bone physiology/development. Previous studies have, however, focused primarily on Hh functions in bone formation, while its roles in bone resorption have not been fully elucidated. Here, we found that cyclopamine (smoothened (Smo) inhibitor), GANT-58 (GLI1 inhibitor), or GANT-61 (GLI1/2 inhibitor) significantly inhibited RANKL-induced osteoclast differentiation of bone marrow-derived macrophages. Although the inhibitory effects were exerted by cyclopamine or GANT-61 treatment during 0-48 h (early stage of osteoclast differentiation) or 48-96 h (late stage of osteoclast differentiation) after RANKL stimulation, GANT-58 suppressed osteoclast formation only during the early stage. These results suggest that the Smo-GLI1/2 axis mediates the whole process of osteoclastogenesis and that GLI1 activation is requisite only during early cellular events of osteoclastogenesis. Additionally, macrophage/osteoclast-specific deletion of Smo in mice was found to attenuate the aging phenotype characterized by trabecular low bone mass, suggesting that blockage of the Hh-signaling pathway in the osteoclast lineage plays a protective role against age-related bone loss. Our findings reveal a specific role of the Hh-signaling pathway in bone resorption and highlight that its inhibitors show potential as therapeutic agents that block osteoclast formation in the treatment of senile osteoporosis.

DOI： 10.3390/ijms21082745

PubMed

researchmap

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

The prognosis of patients with progressive prostate cancers that are hormone refractory and/or have bone metastasis is poor. Multiple therapeutic targets to improve prostate cancer patient survival have been investigated, including orphan GPCRs. In our study, we identified G Protein-Coupled Receptor Class C Group 5 Member A (GPRC5A) as a candidate therapeutic molecule using integrative gene expression analyses of registered data sets for prostate cancer cell lines. Kaplan-Meier analysis of TCGA data sets revealed that patients who have high GPRC5A expression had significantly shorter overall survival. PC3 prostate cancer cells with CRISPR/Cas9-mediated GPRC5A knockout exhibited significantly reduced cell proliferation both in vitro and in vivo. RNA-seq revealed that GPRC5A KO PC3 cells had dysregulated expression of cell cycle-related genes, leading to cell cycle arrest at the G2/M phase. Furthermore, the registered gene expression profile data set showed that the expression level of GPRC5A in original lesions of prostate cancer patients with bone metastasis was higher than that without bone metastasis. In fact, GPRC5A KO PC3 cells failed to establish bone metastasis in xenograft mice models. In addition, our clinical study revealed that GPRC5A expression levels in prostate cancer patient samples were significantly correlated with bone metastasis as well as the patient's Gleason score (GS). Combined assessment with the immunoreactivity of GPRC5A and GS displayed higher specificity for predicting the occurrence of bone metastasis. Together, our findings indicate that GPRC5A can be a possible therapeutic target and prognostic marker molecule for progressive prostate cancer.

DOI： 10.1002/ijc.32554

PubMed

researchmap

Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Cambridge University Press (CUP)  

<title>Abstract</title>
The anabolic effects of androgen on skeletal muscles are thought to be mediated by androgen receptor (AR). Although multiple studies concerning the effects of AR in males have been performed, the molecular mechanisms of AR in skeletal muscles remain unclear. Here we first confirmed that satellite cells from mouse hindlimb muscles express AR. We then generated satellite cell-specific AR knockout mice using <italic>Pax7^CreERT2</italic> and <italic>AR^L2/Y</italic> mice to test whether AR in satellite cells is necessary for muscle regeneration. Surprisingly, we found that muscle regeneration was compromised in both <italic>Pax7^{CreERT2(Fan)/+}</italic> control mice and <italic>Pax7^{CreERT2(Fan)/+};AR^L2/Y</italic> mice compared to <italic>AR^L2/Y</italic> mice. However, <italic>Pax7^{CreERT2(Gaka)/+};AR^L2/Y;R26^tdTomato/+</italic> mice showed no significant differences between control and mutant muscle regeneration. These findings indicate that AR in satellite cells is not essential for muscle regeneration. We propose that <italic>Pax7^{CreERT2(Fan)/+}</italic> control mice should be included in all experiments, because these mice negatively affect the muscle regeneration and show the mild regeneration phenotype.

DOI： 10.1017/exp.2020.14

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The longitudinal growth of long bone, regulated by an epiphyseal cartilaginous component known as the "growth plate", is generated by epiphyseal chondrocytes. The growth plate provides a continuous supply of chondrocytes for endochondral ossification, a sequential bone replacement of cartilaginous tissue, and any failure in this process causes a wide range of skeletal disorders. Therefore, the cellular and molecular characteristics of the growth plate are of interest to many researchers. Hedgehog (Hh), well known as a mitogen and morphogen during development, is one of the best known regulatory signals in the developmental regulation of the growth plate. Numerous animal studies have revealed that signaling through the Hh pathway plays multiple roles in regulating the proliferation, differentiation, and maintenance of growth plate chondrocytes throughout the skeletal growth period. Furthermore, over the past few years, a growing body of evidence has emerged demonstrating that a limited number of growth plate chondrocytes transdifferentiate directly into the full osteogenic and multiple mesenchymal lineages during postnatal bone development and reside in the bone marrow until late adulthood. Current studies with the genetic fate mapping approach have shown that the commitment of growth plate chondrocytes into the skeletal lineage occurs under the influence of epiphyseal chondrocyte-derived Hh signals during endochondral bone formation. Here, we discuss the valuable observations on the role of the Hh signaling pathway in the growth plate based on mouse genetic studies, with some emphasis on recent advances.

DOI： 10.3390/ijms20235840

PubMed

researchmap

Publishing type：Research paper (scientific journal)  

STUDY DESIGN: Case-control study of an animal model. OBJECTIVE: To investigate the factors that are upregulated and potentially related to degenerative changes in the ligamentum flavum (LF) upon mechanical stress concentration. SUMMARY OF BACKGROUND DATA: LF hypertrophy is reported to be associated with mechanical stress. However, few studies, using exhaustive analysis with control subjects, on the molecular mechanisms of LF hypertrophy have been published. METHODS: Fourteen rabbits were used for this study. The first group underwent L2-3 and L4-5 posterolateral fusion with instrumentation and resection of the L3-4 supraspinal muscle to concentrate the mechanical stress on L3-4, whereas the other group underwent a sham operation. The deep layer of the LF from L2-3 to L4-5 in both groups was harvested after 16 weeks. Gene expression was evaluated exhaustively using DNA microarray and real-time polymerase chain reaction (RT-PCR). Fibroblast growth factor 9 (FGF9) protein expression was subsequently examined by immunohistological staining. RESULTS: A total of 680 genes were found to be upregulated upon mechanical stress concentration and downregulated upon mechanical shielding compared with those in the sham group. Functional annotation analysis revealed that these genes not only included those related to the extracellular matrix but also those related to certain FGF families. On RT-PCR validation and immunohistological analysis, we identified that the FGF9 protein increases in the LF upon mechanical stress, especially in the area wherein degenerative changes were frequently identified in the previous literature. CONCLUSION: FGF9 and its pathway are suggested to contribute to the degenerative changes in the LF following mechanical stress. This finding will be helpful in further understanding the molecular mechanism of human LF degeneration.N/A.

DOI： 10.1097/BRS.0000000000003089

Scopus

PubMed

researchmap

Language：English   Publisher：西日本泌尿器科学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：日本筋学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

The tumor suppressor CYLD is a deubiquitinating enzyme that suppresses polyubiquitin-dependent signaling pathways, including the proinflammatory and cell growth-promoting NF-κB pathway. Missense mutations in the CYLD gene are present in individuals with syndromes such as multiple familial trichoepithelioma (MFT), but the pathogenic roles of these mutations remain unclear. Recent studies have shown that CYLD interacts with a RING finger domain protein, mind bomb homologue 2 (MIB2), in the regulation of NOTCH signaling. However, whether MIB2 is an E3 ubiquitin ligase that acts on CYLD is unknown. Here, using the cell-free-based AlphaScreen and pulldown assays to detect protein-protein interactions, along with immunofluorescence assays and murine Mib2 knockout cells and animals, we demonstrate that MIB2 promotes proteasomal degradation of CYLD and enhances NF-κB signaling. Of note, arthritic inflammation was suppressed in Mib2-deficient mice. We further observed that the ankyrin repeat in MIB2 interacts with the third CAP domain in CYLD and that MIB2 catalyzes Lys-48-linked polyubiquitination of CYLD at Lys-338 and Lys-530. MIB2-dependent CYLD degradation activated NF-κB signaling via tumor necrosis factor alpha (TNFα) stimulation and the linear ubiquitination assembly complex (LUBAC). Mib2-knockout mice had reduced serum interleukin-6 (IL-6) and exhibited suppressed inflammatory responses in the K/BxN serum-transfer arthritis model. Interestingly, MIB2 significantly enhanced the degradation of a CYLDP904L variant identified in an individual with MFT, although the molecular pathogenesis of the disease was not clarified here. Together, these results suggest that MIB2 enhances NF-κB signaling in inflammation by promoting the ubiquitin-dependent degradation of CYLD.

DOI： 10.1074/jbc.RA119.010119

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

BACKGROUND: Postoperative pericardial adhesions are considered a risk factor for redo cardiac surgery. Several large- and medium-size animal models of pericardial adhesions have been reported, but small animal models for investigating the development of anti-adhesion materials and molecular mechanisms of this condition are lacking. In this study, we aimed to establish a simple mouse model of pericardial adhesions to address this gap. METHODS: We administered blood, minocycline, picibanil, and talc into the murine pericardial cavity via one-shot injection. Micro-computed tomography analyses of contrast agent-injected mice were carried out for methodological evaluation. We investigated various dosages and treatment durations for molecules identified to be inducers of pericardial adhesion. The adhesive grade was quantified by scoring the strength and volume of adhesion tissues at sacrificed time points. Histological staining with hematoxylin and eosin and Masson's trichrome, and immunostaining for F4/80 or αSMA was performed to investigate the structural features of pericardial adhesions, and pathological features of the pericardial adhesion tissue were compared with human clinical specimens. RESULTS: Administration of talc resulted in the most extensive pericardial adhesions. Micro-computed tomography imaging data confirmed that accurate injection into the pericardial cavity was achieved. We found the optimal condition for the formation of strong pericardial adhesions to be injection of 2.5 mg/g talc for 2 weeks. Furthermore, histological analysis showed that talc administration led to an invasion of myofibroblasts and macrophages in the pericardial cavity and epicardium, consistent with pathological findings in patients with left ventricular assistive devices. CONCLUSIONS: We successfully established a simple mouse model of talc-induced pericardial adhesions, which mimics human pathology and could contribute to solving the clinical issues related to pericardial adhesions.

DOI： 10.1186/s13019-019-0940-9

PubMed

researchmap

Language：Japanese   Publisher：(公財)明治安田厚生事業団  

骨格筋特異的エストロゲン受容体β(ERβ)欠損マウスを用いて、エストロゲンを介した骨格筋量制御メカニズムについて検討した。骨格筋特異的ERβ欠損マウスとしてACTA1-rtTA;tetO-Cre;ERβf/f(mKO)マウスを用いた。また、ERβf/fをコントロール群(CON)として用いた。ドキシサイクリン飲水投与前後における体重増加率を検証したところ、CON群と比較してmKO群で有意に体重増加率が低下していた。握力テストと走行テストでは、CON群と比較してmKO群の顕著な筋力低下をきたした。ノックアウト誘導後、筋重量を定量したところ、雄マウスは遅筋優位のSoleusおよび速筋優位のTAの筋重量に変化がみられなかったが、雌マウスのTAで有意な筋重量低下がみられた。雌のmKOマウスのTAにおいて筋重量の低下が確認されたため、免疫組織化学染色による筋組織像の観察を行った。ノックアウト誘導後、TAを採取しLamininによる筋横断面の染色を行ったところ、mKO群において筋横断面積の顕著な低下がみられた。また、若齢期にみられたERβ欠損マウスの筋力低下や速筋特異的な筋重量低下は性成熟したマウスではみられなかった。

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Resistance training (RT) has been known to be effective in maintaining and improving bone strength, which is based on bone mineral density (BMD) and bone quality. However, it is not clear whether RT is effective in improving bone strength in patients with type-2 diabetes mellitus (T2DM), who have a high risk of fracture. Therefore, we tested the effects of a 6-week RT regimen using percutaneous electrical stimulation in T2DM model rats, male Otsuka Long-Evans Tokushima Fatty (OLETF), and its control, Long-Evans Tokushima Otsuka (LETO). After 6 weeks of RT, tibial BMD in RT legs was significantly higher than that in control (CON) legs in both groups. In diaphyseal cortical bone, bone area/tissue area, and cortical thickness was significantly increased in RT legs compared with CON legs in both groups. Cortical porosity was highly observed in OLETF compared with LETO, but RT improved cortical porosity in both groups. Interestingly, trabecular number, trabecular thickness and trabecular space as well as BMD and bone volume/tissue volume in proximal tibial metaphyseal trabecular bone were significantly improved in RT legs compared with CON legs in both groups. In contrast, connectivity density and structural model index were not affected by RT. These results indicate that the 6-week RT regimen effectively increased BMD and improved bone quality in T2DM model rats as well as control rats. Therefore, RT may have the potential to improve bone strength and reduce fracture risk, even in patients with T2DM.

DOI： 10.14814/phy2.14046

PubMed

researchmap

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Zinc finger and SCAN domain containing 10 (Zscan10) was identified as a novel transcription factor that is involved in osteoclast differentiation in our previous report. However, the biological functions of Zscan10 are not fully understood except its roles in the maintenance of genome stability and pluripotency of embryonic stem cells. Therefore, the purpose of this study was to clarify the function of Zscan10 in somatic cells, especially during osteoclast differentiation. First, Zscan10 KO RAW264 (KO) cells were established by genome editing using CRISPR/Cas9 and single cell sorting. Then, control (Ctrl) and KO cells were differentiated into osteoclasts by RANKL stimulation. We observed that TRAP activity and the expression levels of differentiation marker genes, such as Nfatc1, were significantly increased and the expression of inhibitory factors, such as Irf8, was decreased in KO cells compared to Ctrl cells. These results suggest that Zscan10 might regulate transcription of the genes that negatively control osteoclastogenesis. To understand gene expression profiles controlled by Zscan10, RNA-seq was performed and stringent analyses identified the haptoglobin gene (Hp) as a possible target of Zscan10. In addition, ChIP against Zscan10 revealed that Zscan10 could interact with its binding motif located near the Hp gene locus as well as the transcription start site of Hp, suggesting that Zscan10 can directly regulate transcription of Hp. Finally, to examine the effects of Hp on osteoclastogenesis, KO cells were treated with recombinant Hp (rHp). rHp treatment suppressed TRAP activity of KO cells without affecting cell viability. Furthermore, it has been reported that Hp KO mice exhibit decreased bone mass and increased osteoclast number. Importantly, hemolytic disease patients exhibited decreased serum level of Hp as well as low bone mineral density. Taken together, this study suggests that Zscan10 negatively regulates osteoclast differentiation through transcription of Hp.

DOI： 10.1016/j.bone.2019.02.011

PubMed

researchmap

DOI： 10.4049/jimmunol.1801083

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

We investigated the effects of ibandronate, a bisphosphonate; eldecalcitol, an active vitamin D3 analogue; and combination treatment with both agents on secondary osteoporosis and arthritis using rats with adjuvant-induced arthritis. Arthritis was induced in 8-week-old male Lewis rats. Rats were randomized into four treatment groups and an untreated normal control group: ibandronate, eldecalcitol, ibandronate + eldecalcitol, vehicle, and control. Paw thickness was measured to evaluate arthritis. Joint destruction was evaluated histomorphometrically by the ankle joint stained with Fast Green and safranin O. The femur and lumbar spine were scanned using dual-energy X-ray absorptiometry, and the distal femur was scanned using micro-computed tomography for bone mineral density (BMD) and trabecular microstructural evaluations. Ibandronate and/or eldecalcitol increased BMD in both the lumbar vertebrae and femur and improved several microstructural parameters (bone volume/total volume, structure model index, trabecular number, and trabecular separation of the distal femur). In addition, there was an additive effect of combination treatment compared with single treatments for most trabecular parameters, including BMD and bone volume. However, ibandronate and/or eldecalcitol did not inhibit arthritis and joint destruction. Combination treatment with ibandronate and eldecalcitol may be effective for secondary osteoporosis associated with arthritis.

DOI： 10.2220/biomedres.40.197

PubMed

researchmap

Language：English   Publisher：WILEY  

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Bone mineral density (BMD) is a commonly used diagnostic indicator for bone fracture risk in osteoporosis. Along with low BMD, bone fragility accounts for reduced bone quality in addition to low BMD, but there is no diagnostic method to directly assess the bone quality. In this study, we investigated changes in bone quality using the Raman spectroscopic technique. Sciatic neurectomy (NX) was performed in male C57/BL6J mice (NX group) as a model of disuse osteoporosis, and sham surgery was used as an experimental control (Sham group). Eight months after surgery, we acquired Raman spectral data from the anterior cortical surface of the proximal tibia. We also performed a BMD measurement and micro-CT measurement to investigate the pathogenesis of osteoporosis. Quantitative analysis based on the Raman peak intensities showed that the carbonate/phosphate ratio and the mineral/matrix ratio were significantly higher in the NX group than in the Sham group. There was direct evidence of alterations in the mineral content associated with mechanical properties of bone. To fully understand the spectral changes, we performed principal component analysis of the spectral dataset, focusing on the matrix content. In conclusion, Raman spectroscopy provides reliable information on chemical changes in both mineral and matrix contents, and it also identifies possible mechanisms of disuse osteoporosis.

DOI： 10.3390/molecules23123081

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

While menin plays an important role in preventing T-cell dysfunction, such as senescence and exhaustion, the regulatory mechanisms remain unclear. We found that menin prevents the induction of dysfunction in activated CD8 T cells by restricting the cellular metabolism. mTOR complex 1 (mTORC1) signaling, glycolysis, and glutaminolysis are augmented by menin deficiency. Rapamycin treatment prevents CD8 T-cell dysfunction in menin-deficient CD8 T cells. Limited glutamine availability also prevents CD8 T-cell dysfunction induced by menin deficiency, and its inhibitory effect is antagonized by α-ketoglutarate (α-KG), an intermediate metabolite of glutaminolysis. α-KG-dependent histone H3K27 demethylation seems to be involved in the dysfunction in menin-deficient CD8 T cells. We also found that α-KG activates mTORC1-dependent central carbon metabolism. These findings suggest that menin maintains the T-cell functions by limiting mTORC 1 activity and subsequent cellular metabolism.

DOI： 10.1038/s41467-018-05854-6

PubMed

researchmap

Language：Japanese   Publisher：(公社)日本整形外科学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Longitudinal bone growth progresses by continuous bone replacement of epiphyseal cartilaginous tissue, known as "growth plate", produced by columnar proliferated- and differentiated-epiphyseal chondrocytes. The endochondral ossification process at the growth plate is governed by paracrine signals secreted from terminally differentiated chondrocytes (hypertrophic chondrocytes), and hedgehog signaling is one of the best known regulatory signaling pathways in this process. Here, to investigate the developmental relationship between longitudinal endochondral bone formation and osteogenic progenitors under the influence of hedgehog signaling at the growth plate, genetic lineage tracing was carried out with the use of Gli1CreERT2 mice line to follow the fate of hedgehog-signal-responsive cells during endochondral bone formation. Gli1CreERT2 genetically labeled cells are detected in hypertrophic chondrocytes and osteo-progenitors at the chondro-osseous junction (COJ); these progeny then commit to the osteogenic lineage in periosteum, trabecular and cortical bone along the developing longitudinal axis. Furthermore, in ageing bone, where longitudinal bone growth ceases, hedgehog-signal responsiveness and its implication in osteogenic lineage commitment is significantly weakened. These results show, for the first time, evidence of the developmental contribution of endochondral progenitors under the influence of epiphyseal chondrocyte-derived secretory signals in longitudinally growing bone. This study provides a precise outline for assessing the skeletal lineage commitment of osteo-progenitors in response to growth-plate-derived regulatory signals during endochondral bone formation.

DOI： 10.1007/s00418-018-1641-5

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier B.V.  

Nuclear factor-κB (NF-κB) proteins are transcription factors that play key roles in regulating most immune responses and cell death. Constitutively active NF-κB has been shown to exhibit chemoresistance by inducing anti-apoptosis in tumor cells. Multiple myeloma is known as a constitutive NF-κB activating disease, and the proteasome inhibitor bortezomib is used to treat multiple myeloma and mantle cell lymphoma. We demonstrate here that DANFIN (N,N′-bis-(2,4-dimethyl-phenyl)-ethane-1,2-diamine) functions as an inhibitor of the p65 family proteins and induces chemosensitization to bortezomib in multiple myeloma. DANFIN was found to be an inhibitor of interactions between p65 and IκBα without the inhibition of the DNA binding activity of the p65 protein. In addition, DANFIN affected the IκBα binding region in Rel Homology Domain (RHD) and suppressed the nuclear translocalization of the p65 protein in cells. Furthermore, in multiple myeloma cells, DANFIN suppressed the expression level of NF-κB target genes and induced apoptosis. The combination therapy of DANFIN with bortezomib dramatically enhanced the apoptosis of multiple myeloma cells and indicated a remarkable anti-tumor effect in a multiple-myeloma xenograft mouse model.

DOI： 10.1016/j.bbrc.2017.12.142

Scopus

PubMed

researchmap

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Company of Biologists Ltd  

Transcriptional regulation can be tightly orchestrated by epigenetic regulators. Among these, ubiquitin-like with PHD and RING finger domains 1 (Uhrf1) is reported to have diverse epigenetic functions, including regulation of DNA methylation. However, the physiological functions of Uhrf1 in skeletal tissues remain unclear. Here, we show that limb mesenchymal cell-specific Uhrf1 conditional knockout mice (Uhrf1ΔLimb/ΔLimb) exhibit remarkably shortened long bones that have morphological deformities due to dysregulated chondrocyte differentiation and proliferation. RNA-seq performed on primary cultured chondrocytes obtained from Uhrf1ΔLimb/ΔLimb mice showed abnormal chondrocyte differentiation. In addition, integrative analyses using RNA-seq and MBD-seq revealed that Uhrf1 deficiency decreased genome-wide DNA methylation and increased gene expression through reduced DNA methylation in the promoter regions of 28 genes, including Hspb1, which is reported to be an IL1-related gene and to affect chondrocyte differentiation. Hspb1 knockdown in cKO chondrocytes can normalize abnormal expression of genes involved in chondrocyte differentiation, such as Mmp13. These results indicate that Uhrf1 governs cell type-specific transcriptional regulation by controlling the genome-wide DNA methylation status and regulating consequent cell differentiation and skeletal maturation.

DOI： 10.1242/dev.157412

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

To detect the bone quality loss in osteoporosis, we performed Raman spectroscopic analysis of sciatic nerve resection (NX) mice. Eight months after surgery, lower limbs were collected from the mice and fixed with 70% ethanol. Raman spectra of anterior cortical surface of the proximal tibia at 5 points in each bone were measured by RENISHAW inVia Raman Microscope. Excitation wave length was 785 nm. We also performed DXA and micro CT measurement to confirm the bone mineral density and bone microstructure in the osteoporotic model induced by sciatic nerve resection. In the result of Raman spectroscopy, we detected changes of Raman peak intensity ratio in carbonate/phosphate, mineral/combined proline and hydroxyproline and mineral/phenylalanine. In addition, in the result of micro CT, we found significant changes in VOX BV/TV, Trabecular number, thickness, cancellous bone mineral density, cortical thickness and cortical bone mineral density. The results suggest that not only the bone mineral density but also bone quality reduced in the NX mice. We conclude that Raman spectroscopy is a useful for bone quality assessment as a complementary technique for conventional diagnostics.

DOI： 10.1117/12.2291258

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

This corrects the article DOI: 10.1038/srep42845.

DOI： 10.1038/srep46915

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

C-C chemokine receptor 5 (CCR5) is a co-receptor of HIV. Epidemiological findings suggest that the functional loss of CCR5 is correlated with a lower incidence of bone-destructive diseases as well as of HIV transmission. However, it is not clear whether CCR5 is involved in regulation of the function of bone cells, in addition to that of immune cells. Here we show that blockade of CCR5 using specific antibodies impairs human osteoclast function in vitro. Ccr5-deficient (Ccr5(-/-)) mice presented with dysfunctional osteoclasts and were resistant to osteoporosis induced by receptor activator of nuclear factor kappa-B ligand (RANKL), which triggers osteoporosis independently of inflammatory and immunomodulatory pathways. Furthermore, Ccr5 deficiency impairs the cellular locomotion and bone-resorption activity of osteoclasts, which is associated with the disarrangement of podosomes and adhesion complex molecules including Pyk2. Overall, the data provides evidence that CCR5 has an essential role in bone-destructive conditions through the functional regulation of osteoclasts.

DOI： 10.1038/s41467-017-02368-5

Web of Science

PubMed

researchmap

Language：Japanese   Publisher：愛媛医学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Idiopathic osteonecrosis of the femoral head (IONFH) is an ischemic disorder that causes bone necrosis of the femoral head, resulting in hip joint dysfunction. IONFH is a polygenic disease and steroid and alcohol have already known to increase its risk; however, the mechanism of IONFH remains to be elucidated. We performed a genome-wide association study using similar to 60,000 subjects and found two novel loci on chromosome 20q12 and 12q24. Big data analyses identified LINC01370 as a candidate susceptibility gene in the 20q12 locus. Stratified analysis by IONFH risk factors suggested that the 12q24 locus was associated with IONFH through drinking capacity. Our findings would shed new light on pathophysiology of IONFH.

DOI： 10.1038/s41598-017-14778-y

Web of Science

PubMed

researchmap

Language：Japanese   Publisher：(一社)中部日本整形外科災害外科学会  

researchmap

Language：Japanese   Publisher：(公社)日本整形外科学会  

researchmap

Language：Japanese   Publisher：(一社)日本筋学会  

researchmap

Language：English  

A 58-year-old man was diagnosed with advanced hepatocellular carcinoma with portal vein tumor thrombosis (PVTT). The tumors were multiple and existed in both lobes. Drug-eluting beads transcatheter arterial chemoembolization (DEB-TACE) was performed for the tumors in the left lobe. Embosphere and Hepasphere were selected for embolization of the arterioportal shunt, followed by loaded epirubicin infusion into the left hepatic artery. Computed tomography showed reduction of PVTT. However, liver failure progressed, and the patient died 67 days after DEB-TACE. Autopsy showed that the beads reached the tumor thrombosis in the portal vein. The prognosis of hepatocellular carcinoma with PVTT is poor. Although there are no established treatments for unresectable PVTT, DEB-TACE might be a useful option for such cases.

DOI： 10.1016/j.radcr.2016.11.006

Scopus

PubMed

researchmap

Other Link： http://orcid.org/0000-0002-7466-7356

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Vascular endothelial cell growth factor receptor 2 (VEGFR2) is an essential receptor for the homeostasis of endothelial cells. In this study, we showed that NEDD8-conjugated Cullin3 (CUL3)-based ubiquitin E3 (UbE3) ligase plays a crucial role in VEGFR2 mRNA expression. Human umbilical vein endothelial cells treated with MLN4924, an inhibitor of NEDD8-activating enzyme, or with CUL3 siRNA drastically lost their response to VEGF due to the intense decrease in VEGFR2 expression. Moreover, speckle-type POZ protein (SPOP) and death-domain associated protein (DAXX) were involved in the CUL3 UbE3 ligase complex as a substrate adaptor and a substrate, respectively. Knockdown of SPOP and CUL3 led to the upregulation of DAXX protein and downregulation of VEGFR2 levels. These levels were inversely correlated with one another. In addition, simultaneous knockdown of SPOP and DAXX completely reversed the downregulation of VEGFR2 levels. Moreover, the CUL3-SPOP-DAXX axis had the same effects on NOTCH1, DLL4 and NRP1 expression. Taken together, these findings suggest that the CUL3SPOP-DAXX axis plays a very important role in endothelial cell function by targeting key angiogenic regulators.

DOI： 10.1038/srep42845

Web of Science

researchmap

Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

To evaluate the bone quality in the osteoporosis, we generated sciatic nerve resection (NX) mice as an osteoporosis model and analyzed by Raman spectroscopy. Raman spectra were measured in anterior cortical surface of the proximal tibia at 5 points in each bone. After that, the samples were fixed with 70% ethanol. We then performed DXA and μCT measurement. Raman peak intensity ratios were significantly different between NX and Control. Those changes in the Raman peak intensity ratios may reflect loss of bone quality in the osteoporosis model. Raman spectroscopy is a promising technique for measuring the bone quality and bone strength.

DOI： 10.1117/12.2274980

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Bone Morphogenetic Proteins (BMPs) strongly induce the recruitment and differentiation of mesenchymal progenitor cells into mature osteoblasts, but also directly and indirectly stimulate differentiation of osteoclast progenitor cells and acceleration of mature osteoclasts function leading excessive bone resorption. Bisphosphonates, such as zoledronate (ZOL), inhibit osteoclasts function and osteoclasts mediated bone resorption. The short or middle term effect of BMP5 and bisphosphonates on bone formation were previously reported, but there was no study that argue about the long term effect of bisphosphonates on BMP-induced bone anabolism. The present study demonstrated that the local administration of ZOL with recombinant human BMP-2 (rh-BMP-2) using beta tricalcium phosphate ((3TCP) as a carrier had superior efficacy not only to augment the BMP-induced new ectopic bone formation but to maintain the trabecular bone structure inside the new bone for long period. Histological analysis showed that rh-BMP-2/I3-TCP composite induced trabecular bone resorption especially inside the new bone nodules over time, whereas no trabecular bone resorption was seen in rh-BMP-2/ZOL/P-TCP composite reducing the number of TRAP-positive cells. Thus, inhibition of bone resorption by bisphosphonate, such as ZOL, would be one of the advantageous ways to augment the new bone formation induced by rh-BMP-2, and moreover local co-application of ZOL using D-TCP as a carrier can be a useful material for long term suppression of osteoclastic resorption and thereby maintain the structure of new bone formation induced by rh-BMP-2. (C) 2016 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2016.10.034

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：World Scientific Publishing Co. Pte Ltd  

Purpose: Bone morphogenetic proteins (BMPs) strongly induce osteogenesis. However, BMPs also directly or indirectly stimulate catabolic osteoclast activity, leading to strong bone resorption, especially in the bone marrow. The aim of this study was to investigate whether the combination of a local recombinant human BMP-2 (rh-BMP-2)/beta-tricalcium phosphate (β-TCP) composite with systemically administrated bisphosphonate, zoledronate (ZOL) could promote osteogenesis in a rabbit model. Methods: β-TCP columns, with or without rh-BMP-2 (30 μg/column), were implanted into the left femur canal of 20 rabbits. The animals were injected with 0.4mg of ZOL or saline 1 week after implantation. The implants were evaluated by micro-computed tomography (μ-CT) and histology 6 weeks after implantation. Results: μ-CT data revealed that the bone volume/tissue volume ratio of bone nodules inside β-TCP columns in combination with rh-BMP-2 and ZOL was significantly higher than that of β-TCP columns treated with rh-BMP-2, ZOL, or neither. Histological evaluation also revealed that significantly more new bone formed inside β-TCP columns treated with rh-BMP-2 and ZOL than inside β-TCP columns treated with rh-BMP-2, ZOL, or neither. Conclusion: This combination therapy contributed to the maintenance of the newly formed BMP-2-induced bone structure in the bone marrow.

DOI： 10.1142/S0218957716500159

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：PUBLIC LIBRARY SCIENCE  

TGF-beta is a multifunctional cytokine that is involved in cell proliferation, differentiation and function. We previously reported an essential role of the TGF-beta-Smad2/3 pathways in RANKL-induced osteoclastogenesis. Using chromatin immunoprecipitation followed by sequencing, we comprehensively identified Smad2/3 target genes in bone marrow macrophages. These genes were enriched in the gene population upregulated by TGF-beta and downregulated by RANKL. Recent studies have revealed that histone modifications, such as trimethylation of histone H3 lysine 4 (H3K4me3) and lysine 27 (H3K27me3), critically regulate key developmental steps. We identified Nedd9 as a Smad2/3 target gene whose histone modification pattern was converted from H3K4me3(+)/H3K4me27(+) to H3K4me3 (+)/H3K4me27(-) by TGF-beta. Nedd9 expression was increased by TGF-beta and suppressed by RANKL. Overexpression of Nedd9 partially rescued an inhibitory effect of a TGF-beta inhibitor, while gene silencing of Nedd9 suppressed RANKL-induced osteoclastogenesis. RANKL-induced osteoclastogenesis were reduced and stimulatory effects of TGF-beta on RANKL-induced osteoclastogenesis were partially abrogated in cells from Nedd9-deficient mice although knockout mice did not show abnormal skeletal phenotypes. These results suggest that Nedd9 is a Smad2/3 target gene implicated in RANKL-induced osteoclastogenesis.

DOI： 10.1371/journal.pone.0157992

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

sFRP4 is an extracellular Wnt antagonist that fine-tunes its signal activity by direct binding to Wnts. Bone fragility under oxidative stress by diabetes and aging is partly related to the suppression of the Wnt signal through upregulated sFRP4. Here, to explore the functions of sFRP4 as a balancer molecule in bone development and remodeling, we analyzed the sFRP4 knock-in mouse strain. X-gal and immunohistochemically stained signals in sFRP4-LacZ heterozygous mice were detectable in restricted areas, mostly in osteoblasts and osteoclasts, of the femoral diaphysis after neonatal and postnatal stages. Histological and mu CT analyses showed increased trabecular bone mass with alteration of the Wnt signal and osteogenic activity in sFRP4 mutants; this augmented the effect of the buildup of trabecular bone during the ageing period. Our results indicate that sFRP4 plays a critical role in bone development and remodeling by regulating osteoblasts and osteoclasts, and that its functional loss prevents age-related bone loss in the trabecular bone area. These findings imply that sFRP4 functions as a key potential endogenous balancer of the Wnt signaling pathway by efficiently having direct influence on both bone formation and bone absorption during skeletal bone development and maintenance through remodeling.

DOI： 10.1038/srep25198

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

DNA methylation is closely involved in the regulation of cellular differentiation, including chondrogenic differentiation of mesenchymal stem cells. Recent studies showed that Ten-eleven translocation (TET) family proteins converted 5-methylcytosine (5mC) to 5-hydroxymethylcytosine, 5-formylcytosine and 5carboxylcytosine by oxidation. These reactions constitute potential mechanisms for active demethylation of methylated DNA. However, the relationship between the DNA methylation patterns and the effects of TET family proteins in chondrocyte differentiation is still unclear. In this study, we showed that DNA hydroxylation of 5mC was increased during chondrocytic differentiation of C3H10T1/2 cells and that the expression of Tet1 was particularly enhanced. Moreover, knockdown experiments revealed that the downregulation of Tet1 expression caused decreases in chondrogenesis markers such as type 2 and type 10 collagens. Furthermore, we found that TET proteins had a site preference for hydroxylation of 5mC on the Insulin-like growth factor 1 (Igf1) promoter in chondrocytes. Taken together, we showed that the expression of Tet1 was specifically facilitated in chondrocyte differentiation and Tet1 can regulate chondrocyte marker gene expression presumably through its hydroxylation activity for DNA.

DOI： 10.1016/j.bbrep.2015.11.009

Scopus

researchmap

DOI： 10.1016/j.bbadis.2015.08.018

PubMed

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Osteoclast differentiation is associated with both normal bone homeostasis and pathological bone diseases such as osteoporosis. Several transcription factors can regulate osteoclast differentiation, including c-fos and Nfatc1. Using genome-wide DNase-seq analysis, we found a novel transcription factor, SREBP2, that participates in osteoclast differentiation in vitro. Here, we asked whether SREBP2 actually plays a role in controlling bone metabolism in vivo. To answer this question, RAW264 cells, primary cultured osteoclasts and the mouse RANKL-induced bone loss model were treated with fatostatin, a small molecule inhibitor specific for the activation of SREBP. When cells were treated with fatostatin, osteoclast differentiation was impaired. Similar results were obtained following treatment with siRNA for Srebf2, the gene coding for SREBP2. In vivo, mu CT analyses showed that fatostatin treatment preserved bone mass and structure in the proximal tibial trabecular bone in the mouse RANKL-induced bone loss model. In addition, bone histomorphometric analysis revealed that the protection of bone mass by fatostatin might have been achieved by suppression of RANKL-mediated osteoclast differentiation. These results indicated that the novel transcription factor SREBP2 physiologically functions in osteoclast differentiation in vivo and might be a possible therapeutic target for bone diseases. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.bbadis.2015.08.018

Web of Science

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

We have previously reported that transforming growth factor (TGF-) plays an essential role in receptor activator of nuclear factor-B ligand (RANKL)-induced osteoclastogenesis. However, the detailed underlying molecular mechanisms still remain unclear. Formaldehyde-assisted isolation of regulatory elements (FAIRE) and chromatin immunoprecipitation (ChIP) followed by sequencing (FAIRE-seq and ChIP-seq) analyses indicated the cooperation of Smad2/3 with c-Fos during osteoclastogenesis. Biochemical analysis and immunocytochemical analysis revealed that physical interaction between Smad2/3 and c-Fos is required for their nuclear translocation. The gene expression of nuclear factor of activated T-cells, cytoplasmic 1 (Nfatc1), a key regulator of osteoclastogenesis, was regulated by RANKL and TGF-, and c-Fos binding to open chromatin sites was suppressed by inhibition of TGF- signaling by SB431542. Conversely, Smad2/3 binding to Nfatc1 was impaired by c-Fos deficiency. These results suggest that TGF- regulates RANKL-induced osteoclastogenesis through reciprocal cooperation between Smad2/3 and c-Fos. (c) 2014 American Society for Bone and Mineral Research.

DOI： 10.1002/jbmr.2418

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER JAPAN KK  

The efficacy of autologous bone grafting in repairing nonunion fractures, large bone defects and spinal instability is widely accepted. However, the cellular and molecular mechanisms underlying new bone formation in bone grafting have yet to be fully elucidated. The purpose of this study was to clarify the fate, origin and the contribution of the cells within the grafted bone.
This study was designed to investigate the role and fate of cells contained in the grafted bone and their contribution to new bone formation in the graft in an animal model. Middiaphyseal cylindrical bone samples obtained from green fluorescent protein (GFP) transgenic and wild-type rats were transplanted into the back muscle of wild-type and GFP rats, respectively. The transplanted bones were evaluated by immunohistochemistry, in situ hybridization and quantitative reverse transcription polymerase chain reaction.
Immunohistochemical analyses showed that all the cells in the newly formed bone originated from the grafted bone, and osteoblasts were gradually replaced by host cells. Conversely, osteoclasts were immediately replaced by host cells 2 weeks after the bone graft. In addition, expression of bone morphogenetic protein (Bmp)-4, Bmp receptors and Noggin in the grafted bone was significantly upregulated before new bone formation occurred, indicating that the grafted cells might contribute to the recruitment of mesenchymal cells into the graft bed.
This study revealed the possible molecular mechanisms of the contribution of cells contained in grafted bone to facilitate new bone formation.

DOI： 10.1007/s00776-014-0673-5

Web of Science

PubMed

researchmap

Language：English   Publishing type：Part of collection (book)   Publisher：Springer International Publishing  

Patients with osteoporosis have high risks for vertebral and non-vertebral fractures
therefore, these patients should be adequately diagnosed and treated for prevention of fractures. It is essential to treat patients appropriately and sufficiently that the physicians must understand the mechanisms underlying osteoporosis and physiological bone homeostasis. The large population of osteoporosis is postmenopausal osteoporosis, which is categorized in primary osteoporosis. Postmenopausal osteoporosis is caused by deficiency of estrogen. Estrogen exerts its osteoprotective effects directly and indirectly to bone tissue. Also, secondary osteoporosis can be induced by various pathologic conditions, such as hyperparathyroidism, glucocorticoid treatment, and inflammatory diseases. Clarification of the molecular basis underlying the pathophysiology of osteoporosis will open the window to develop novel therapeutic strategy for osteoporosis.

DOI： 10.1007/978-3-319-20777-3_33

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The Cdk-related protein kinase Pctaire1/Cdk16 is abundantly expressed in brain, testis and skeletal muscle. Functional roles of Pctaire1 such as regulation of neuron migration and neurite outgrowth thus far have been mainly elucidated in the field of nervous system development. Although these regulations based on cytoskeletal rearrangements evoke a possible role of Pctaire1 in the development of skeletal muscle, little is known in this regard. In this study, we demonstrated that myogenic differentiation and subsequent fusion is promoted in Pctaire1 overexpressing cells, and conversely, is inhibited in the knockdown cells. Furthermore, our findings suggest that Pctaire1 exerts promyogenic effects by regulating myoblast migration and process formation during skeletal myogenesis. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.febslet.2014.05.060

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY  

Clarification of the mechanisms underlying osteoclast differentiation enables us to understand the physiology of bone metabolism as well as the pathophysiology of bone diseases such as osteoporosis. Recently, it has been reported that epigenetics can determine cell fate and regulate cell type-specific gene expression. However, little is known about epigenetics during osteoclastogenesis. To reveal a part of epigenetics, especially focused on chromatin dynamics, during early osteoclastogenesis and to identify novel transcription factors involved in osteoclastogenesis, we performed a genome-wide analysis of open chromatin during receptor activator of NF-kappa B ligand (RANKL)-induced osteoclastogenesis using DNase I hypersensitive sites sequencing (DNase-seq). DNase-seq was performed using the extracted nuclei from RAW264 cells treated with or without RANKL for 24 hours, followed by several bioinformatic analyses. DNase I hypersensitive sites (DHSs) were dynamically changed during RANKL-induced osteoclastogenesis and they accumulated in promoter regions. The distributions of DHSs among cis-regulatory DNA regions were identical regardless of RANKL stimulation. Motif discovery analysis successfully identified well-known osteoclastogenic transcription factors including Jun, CREB1, FOS, ATF2, and ATF4, but also novel transcription factors for osteoclastogenesis such as Zscan10, Atf1, Nrf1, and Srebf2. siRNA knockdown of these identified novel transcription factors impaired osteoclastogenesis. Taken together, DNase-seq is a useful tool for comprehension of epigenetics, especially chromatin dynamics during osteoclastogenesis and for identification of novel transcription factors involved in osteoclastogenesis. This study may reveal underlying mechanisms that determine cell type-specific differentiation of bone cells and may lead to investigation of novel therapeutic targets for osteoporosis. (C) 2014 American Society for Bone and Mineral Research.

DOI： 10.1002/jbmr.2229

Web of Science

PubMed

researchmap

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Academic Press Inc.  

Bone mass is regulated by various molecules including endogenous factors as well as exogenous factors, such as nutrients and pollutants. Aryl hydrocarbon receptor (AhR) is known as a dioxin receptor and is responsible for various pathological and physiological processes. However, the role of AhR in bone homeostasis remains elusive because the cell type specific direct function of AhR has never been explored in vivo. Here, we show the cell type specific function of AhR in vivo in bone homeostasis. Systemic AhR knockout (AhRKO) mice exhibit increased bone mass with decreased resorption and decreased formation. Meanwhile, osteoclast specific AhRKO (AhRΔOc/ΔOc) mice have increased bone mass with reduced bone resorption, although the mice lacking AhR in osteoblasts have a normal bone phenotype. Even under pathological conditions, AhRΔOc/ΔOc mice are resistant to sex hormone deficiency-induced bone loss resulting from increased bone resorption. Furthermore, 3-methylcholanthrene, an AhR agonist, induces low bone mass with increased bone resorption in control mice, but not in AhR ΔOc/ΔOc mice. Taken together, cell type specific in vivo evidence for AhR functions indicates that osteoclastic AhR plays a significant role in maintenance of bone homeostasis, suggesting that inhibition of AhR in osteoclasts can be beneficial in the treatment of osteoporosis. © 2014 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2014.05.114

Web of Science

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ENDOCRINE SOC  

The bulbocavernosus (BC) is a sexually dimorphic muscle observed only in males. Androgen receptor knockout mouse studies show the loss of BC formation. This suggests that androgen signaling plays a vital role in its development. Androgen has been known to induce muscle hypertrophy through satellite cell activation and myonuclei accretion during muscle regeneration and growth. Whether the same mechanism is present during embryonic development is not yet elucidated. To identify the mechanism of sexual dimorphism during BC development, the timing of morphological differences was first established. It was revealed that the BC was morphologically different between male and female mice at embryonic day (E) 16.5. Differences in the myogenic process were detected at E15.5. The male BC possesses a higher number of proliferating undifferentiated myo-blasts. To identify the role of androgen signaling in this process, muscle-specific androgen receptor (AR) mutation was introduced, which resulted in no observable phenotypes. Hence, the expression of AR in the BC was examined and found that the AR did not colocalize with any muscle markers such as Myogenic differentiation 1, Myogenin, and paired box transcription factor 7. It was revealed that the mesenchyme surrounding the BC expressed AR and the BC started to express AR at E15.5. AR mutation on the nonmyocytic cells using spalt-like transcription factor 1 (Sall1) Cre driver mouse was performed, which resulted in defective BC formation. It was revealed that the number of proliferating undifferentiated myoblasts was reduced in the Sall1 Cre: AR(L-/Y) mutant embryos, and the adult mutants were devoid of BC. The transition of myoblasts from proliferation to differentiation is mediated by cyclin-dependent kinase inhibitors. An increased expression of p21 was observed in the BC myoblast of the Sall1 Cre: AR(L-/Y) mutant and wild-type female. Altogether this study suggests that the nonmyocytic AR may paracrinely regulate the proliferation of myoblast possibly through inhibiting p21 expression in myoblasts of the BC.

DOI： 10.1210/en.2014-1008

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Bone is a highly vascularized organ, thus angiogenesis is a vital process during bone remodeling. However, the role of vascular systems in bone remodeling is not well recognized. Here we show that netrin-4 inhibits osteoclast differentiation in vitro and in vivo. Co-cultures of bone marrow macrophages with vascular endothelial cells markedly inhibited osteodast differentiation. Adding a neutralizing antibody, or RNA interference against netrin-4, restored in vitro osteoclast differentiation. Administration of netrin-4 prevented bone loss in an osteoporosis mouse model by decreasing the osteoclast number. We propose that vascular endothelial cells interact with bone in suppressing bone through netrin-4. (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

DOI： 10.1016/j.febslet.2014.05.009

Web of Science

PubMed

researchmap

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Estrogens are well known steroid hormones necessary to maintain bone health. In addition, mechanical loading, in which estrogen signaling may intersect with the Wnt/beta-catenin pathway, is essential for bone maintenance. As osteocytes are known as the major mechanosensory cells embedded in mineralized bone matrix, osteocyte ER alpha deletion mice (ER alpha(Delta Ocy/Delta Ocy)) were generated by mating ERa floxed mice with Dmp1-Cre mice to determine the role of ER alpha in osteocytes. Trabecular bone mineral density of female, but not male ER alpha(Delta Ocy/Delta Ocy) mice was significantly decreased. Bone formation parameters in ER alpha(Delta Ocy/Delta Ocy) were significantly decreased while osteoclast parameters were unchanged. This suggests that ERot in osteocytes exerts osteoprotective function by positively controlling bone formation. To identify potential targets of ER alpha, gene array analysis of Dmp1-GFP osteocytes sorted by FACS from ER alpha(Delta Ocy/Delta Ocy) and control mice was performed. Gene expression microarray followed by gene ontology analyses revealed that osteocytes from ER alpha(Delta Ocy/Delta Ocy) highly expressed genes categorized in 'Secreted' when compared to control osteocytes. Among them, expression of Mdk and Sostdc1, both of which are Wnt inhibitors, was significantly increased without alteration of expression of the mature osteocyte markers such as Sost and beta-catenin. Moreover, hindlimb suspension experiments showed that trabecular bone loss due to unloading was greater in ER alpha(Delta Ocy/Delta Ocy) mice without cortical bone loss. These data suggest that ERot in osteocytes has osteoprotective functions in trabecular bone formation through regulating expression of Wnt antagonists, but conversely plays a negative role in cortical bone loss due to unloading. Published by Elsevier Inc.

DOI： 10.1016/j.bone.2013.12.005

Web of Science

PubMed

researchmap

Authorship：Corresponding author  

DOI： 10.4161/adip.25731

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

Chondrocyte differentiation is controlled by various regulators, such as Sox9 and Runx2, but the process is complex. To further understand the precise underlying molecular mechanisms of chondrocyte differentiation, we aimed to identify a novel regulatory factor of chondrocyte differentiation using gene expression profiles of micromass-cultured chondrocytes at different differentiation stages. From the results of microarray analysis, the autoimmune regulator, Aire, was identified as a novel regulator. Aire stable knockdown cells, and primary cultured chondrocytes obtained from Aire(-/-) mice, showed reduced mRNA expression levels of chondrocyte-related genes. Over-expression of Aire induced the early stages of chondrocyte differentiation by facilitating expression of Bmp2. A ChIP assay revealed that Aire was recruited on an Airebinding site (T box) in the Bmp2 promoter region in the early stages of chondrocyte differentiation and histone methylation was modified. These results suggest that Aire can facilitate early chondrocyte differentiation by expression of Bmp2 through altering the histone modification status of the promoter region of Bmp2.
Taken together, Aire might play a role as an active regulator of chondrocyte differentiation, which leads to new insights into the regulatory mechanisms of chondrocyte differentiation. (C) 2013 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2013.07.001

Web of Science

PubMed

researchmap

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

The pathology of rheumatoid arthritis (RA) is ameliorated during pregnancy and deteriorated after delivery. Thus, female sex hormones could be involved in the pathogenesis of RA. However, the effects of estrogen and progesterone on the development and progression of RA have been unclear. In this study, we analyzed the effects of female hormones on the pathogenesis of RA by performing ovariectomy (OVX) and hormone implantation in the SKG mouse model of human RA. OVX mice showed severe arthritis and cartilage destruction with increased serum levels of TNF-alpha and IL-6, when compared with sham-operated mice. In contrast, estrogen-treated mice exhibited remarkable suppression of arthritis, with no bone erosion, little synovial hyperplasia and little infiltration of immune cells. Moreover, serum levels of TNF-a. and IL-6 were decreased. In progesterone-treated mice, mild synovial hyperplasia and no immune cell infiltration were observed, with decreased serum levels of IL-6. These results suggest that female hormones, estrogen and progesterone, can play roles in the remission of RA. (c) 2013 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2013.03.111

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：5  

PHF2 is a JmjC family histone demethylase that removes the methyl group from H3K9me2 and works as a coactivator for several metabolism-related transcription factors. In this study, we examined the in vivo role of PHF2 in mice. We generated Phf2 floxed mice, systemic Phf2 null mice by crossing Phf2 floxed mice with CMV-Cre transgenic mice, and tamoxifen-inducible Phf2 knockout mice by crossing Phf2 floxed mice with Cre-ERT2 transgenic mice. Systemic Phf2 null mice had partial neonatal death and growth retardation and exhibited less adipose tissue and reduced adipocyte numbers compared with control littermates. Tamoxifen-induced conditional knockout of PHF2 resulted in impaired adipogenesis in stromal vascular cells from the adipose tissue of tamoxifen-inducible Phf2 knockout mice as well as of Phf2 knocked-down 3T3-L1 cells. PHF2 interacts with CEBPA and demethylates H3K9me2 in the promoters of CEBPA-regulated adipogenic genes. These findings suggest that PHF2 histone demethylase potentiates adipogenesis through interaction with CEBPA in vivo. Taken together, PHF2 may be a novel therapeutic target in the treatment of obesity and the metabolic syndrome. © 2013 by the American Diabetes Association.

DOI： 10.2337/db12-0628

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

PHF2 is a JmjC family histone demethylase that removes the methyl group from H3K9me2 and works as a coactivator for several metabolism-related transcription factors. In this study, we examined the in vivo role of PHF2 in mice. We generated Phf2 floxed mice, systemic Phf2 null mice by crossing Phf2 floxed mice with CMV-Cre transgenic mice, and tamoxifen-inducible Phf2 knockout mice by crossing Phf2 floxed mice with Cre-ERT2 transgenic mice. Systemic Phf2 null mice had partial neonatal death and growth retardation and exhibited less adipose tissue and reduced adipocyte numbers compared with control littermates. Tamoxifen-induced conditional knockout of PHF2 resulted in impaired adipogenesis in stromal vascular cells from the adipose tissue of tamoxifen-inducible Phf2 knockout mice as well as of Phf2 knocked-down 3T3-L1 cells. PHF2 interacts with CEBPA and demethylates H3K9me2 in the promoters of CEBPA-regulated adipogenic genes. These findings suggest that PHF2 histone demethylase potentiates adipogenesis through interaction with CEBPA in vivo. Taken together, PHF2 may be a novel therapeutic target in the treatment of obesity and the metabolic syndrome.

DOI： 10.2337/db12-0628

PubMed

researchmap

Language：English   Publisher：AMER PHYSIOLOGICAL SOC  

Imai Y, Youn M-Y, Inoue K, Takada I, Kouzmenko A, Kato S. Nuclear Receptors in Bone Physiology and Diseases. Physiol Rev 93: 481-523, 2013; doi: 10.1152/physrev.00008.2012.-During the last decade, our view on the skeleton as a mere solid physical support structure has been transformed, as bone emerged as a dynamic, constantly remodeling tissue with systemic regulatory functions including those of an endocrine organ. Reflecting this remarkable functional complexity, distinct classes of humoral and intracellular regulatory factors have been shown to control vital processes in the bone. Among these regulators, nuclear receptors (NRs) play fundamental roles in bone development, growth, and maintenance. NRs are DNA-binding transcription factors that act as intracellular transducers of the respective ligand signaling pathways through modulation of expression of specific sets of cognate target genes. Aberrant NR signaling caused by receptor or ligand deficiency may profoundly affect bone health and compromise skeletal functions. Ligand dependency of NR action underlies a major strategy of therapeutic intervention to correct aberrant NR signaling, and significant efforts have been made to design novel synthetic NR ligands with enhanced beneficial properties and reduced potential negative side effects. As an example, estrogen deficiency causes bone loss and leads to development of osteoporosis, the most prevalent skeletal disorder in postmenopausal women. Since administration of natural estrogens for the treatment of osteoporosis often associates with undesirable side effects, several synthetic estrogen receptor ligands have been developed with higher therapeutic efficacy and specificity. This review presents current progress in our understanding of the roles of various nuclear receptor-mediated signaling pathways in bone physiology and disease, and in development of advanced NR ligands for treatment of common skeletal disorders.

DOI： 10.1152/physrev.00008.2012

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ENDOCRINE SOC  

The physiological and beneficial actions of vitamin D in bone health have been experimentally and clinically proven in mammals. The active form of vitamin D [1 alpha,25(OH)(2)D-3] binds and activates its specific nuclear receptor, the vitamin D receptor (VDR). Activated VDR prevents the release of calcium from its storage in bone to serum by stimulating intestinal calcium absorption and renal reabsorption. However, the direct action of VDR in bone tissue is poorly understood because serum Ca2+ homeostasis is maintained through tightly regulated ion transport by the kidney, intestine, and bone. In addition, conventional genetic approaches using VDR knockout (VDR-KO, VDR-/-) mice could not identify VDR action in bone because of the animals' systemic defects in calcium metabolism. In this study, we report that systemic VDR heterozygous KO (VDR+/L-) mice generated with the Cre/loxP system as well as conventional VDR heterozygotes (VDR+/-)showed increased bone mass in radiological assessments. Because mineral metabolism parameters were unaltered in both types of mice, these bone phenotypes imply that skeletal VDR plays a role in bone mass regulation. To confirm this assumption, osteoblast-specific VDR-KO (VDR Delta Ob/Delta Ob) mice were generated with 2.3 kb alpha 1(I)-collagen promoter-Cre transgenic mice. They showed a bone mass increase without any dysregulation of mineral metabolism. Although bone formation parameters were not affected in bone histomorphometry, bone resorption was obviously reduced in VDR Delta Ob/Delta Ob mice because of decreased expression of receptor activator of nuclear factor kappa-B ligand (an essential molecule in osteoclastogenesis) in VDR Delta Ob/Delta Ob osteoblasts. These findings establish that VDR in osteoblasts is a negative regulator of bone mass control. (Endocrinology 154: 1008-1020, 2013)

DOI： 10.1210/en.2012-1542

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC  

Osteoclastogenesis is a highly regulated process governed by diverse classes of regulators. Among them, nuclear factor of activated T-cells calcineurin-dependent 1 (NFATc1) is the primary osteoclastogenic transcription factor, and its expression is transcriptionally induced during early osteoclastogenesis by receptor activation of nuclear factor kappa B ligand (RANKL), an osteoclastogenic cytokine. Here, we report the novel enzymatic function of JMJD5, which regulates NFATc1 protein stability. Among the tested Jumonji C (JmjC) domain-containing proteins, decreased mRNA expression levels during osteoclastogenesis were found for JMJD5 in RAW264 cells stimulated by RANKL. To examine the functional role of JMJD5 in osteoclast differentiation, we established stable JMJD5 knockdown cells, and osteoclast formation was assessed. Down-regulated expression of JMJD5 led to accelerated osteoclast formation together with induction of several osteoclast-specific genes such as Ctsk and DC-STAMP, suggesting that JMJD5 is a negative regulator in osteoclast differentiation. Although JMJD5 was recently reported as a histone demethylase for histone H3K36me2, no histone demethylase activity was detected in JMJD5 in vitro or in living cells, even for other methylated histone residues. Instead, JMJD5 co-repressed transcriptional activity by destabilizing NFATc1 protein. Protein hydroxylase activity mediated by the JmjC domain in JMJD5 was required for the observed functions of JMJD5. JMJD5 induced the association of hydroxylated NFATc1 with the E3 ubiquitin ligase Von Hippel-Lindau tumor suppressor (VHL), thereby presumably facilitating proteasomal degradation of NFATc1 via ubiquitination. Taken together, the present study demonstrated that JMJD5 is a post-translational co-repressor for NFATc1 that attenuates osteoclastogenesis.

DOI： 10.1074/jbc.M111.323105

Web of Science

PubMed

researchmap

Language：Japanese   Publisher：The Japanese Society of Toxicology  

DOI： 10.14869/toxpt.39.1.0.S1-5.0

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Small interfering RNA (siRNA) is useful tool for specific and efficient knockdown of disease-related genes. However, in vivo applications of siRNA are limited due to difficulty in its efficient delivery to target cells. In this study, we investigated the efficacy of a biodegradable hydrogel, poly-D,L-lactic acid-p-dioxanone-polyethylene glycol block co-polymer (PLA-DX-PEG), as a siRNA carrier. PLA-DX-PEG pellets with or without fluorescein-labeled dsRNA were implanted into mouse dosal muscle pouches. The cellular uptake of dsRNA surround the polymer was confirmed by fluorescent microscopy. The fluorescence intensity was dose-dependent of the dsRNA, and exhibited a time-dependent decrease. To investigate its biological efficiency, noggin (antagonoist to BMPs) gene-silencing with siRNA (siRNA/Noggin) was examined by the amount of suppression of BMP-2-induced noggin expression and the level of performance of BMP, indicated by ectopic bone formation. Noggin gene expression induced by BMP-2 was suppressed by addition of siRNA/Noggin to the implant, and the ectopic bone formation induced by implants with both BMP-2 and siRNA/Noggin was significantly greater than those induced by implants with BMP-2 alone. These results indicate the efficacy of local delivery of siRNAs by PLA-DX-PEG polymer, which intensified bone-inducing effects of BMP and promoted new bone formation by suppressing gene expression of Noggin. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biomaterials.2011.08.026

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：7378  

Chromatin reorganization is governed by multiple post-translational modifications of chromosomal proteins and DNA. These histone modifications are reversible, dynamic events that can regulate DNA-driven cellular processes. However, the molecular mechanisms that coordinate histone modification patterns remain largely unknown. In metazoans, reversible protein modification by O-linked N-acetylglucosamine (GlcNAc) is catalysed by two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). However, the significance of GlcNAcylation in chromatin reorganization remains elusive. Here we report that histone H2B is GlcNAcylated at residue S112 by OGT in vitro and in living cells. Histone GlcNAcylation fluctuated in response to extracellular glucose through the hexosamine biosynthesis pathway (HBP). H2B S112 GlcNAcylation promotes K120 monoubiquitination, in which the GlcNAc moiety can serve as an anchor for a histone H2B ubiquitin ligase. H2B S112 GlcNAc was localized to euchromatic areas on fly polytene chromosomes. In a genome-wide analysis, H2B S112 GlcNAcylation sites were observed widely distributed over chromosomes including transcribed gene loci, with some sites co-localizing with H2B K120 monoubiquitination. These findings suggest that H2B S112 GlcNAcylation is a histone modification that facilitates H2BK120 monoubiquitination, presumably for transcriptional activation.

DOI： 10.1038/nature10656

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Bone undergoes remodeling consisting of osteoclastic bone resorption followed by osteoblastic bone formation throughout life. Although the effects of bone morphogenetic protein (BMP) signals on osteoblasts have been studied extensively, the function of BMP signals in osteoclasts has not been fully elucidated. To delineate the function of BMP signals in osteoclasts during bone remodeling, we deleted BMP receptor type IA (Bmpr1a) in an osteoclast-specific manner using a knock-in Cre mouse line to the cathepsin K locus (Ctsk(Cre/+); Bmpr1a(flox/flox), designated as Bmpr1a(Delta Oc/Delta Oc)). Cre was specifically expressed in multinucleated osteoclasts in vivo. Cre-dependent deletion of the Bmpr1a gene occurred at 4 days after cultivation of bone marrow macrophages obtained from Bmpr1a(Delta Oc/Delta Oc) with RANKL. These results suggested that Bmpr1a was deleted after formation of osteoclasts in Bmpr1a(Delta Oc/Delta Oc) mice. Expression of bone-resorption markers increased, thus suggesting that BMPRIA signaling negatively regulates osteoclast differentiation. Trabeculae in tibia and femurs were thickened in 3.5-, 8-, and 12-week-old Bmpr1a(Delta Oc/Delta Oc) mice. Bone histomorphometry revealed increased bone volume associated with increased osteoblastic bone-formation rates (BFR) in the remodeling bone of the secondary spongiosa in Bmpr1a(Delta Oc/Delta Oc) tibias at 8 weeks of age. For comparison, we also induced an osteoblast-specific deletion of Bmpr1a using Col1a1-Cre. The resulting mice showed increased bone volume with marked decreases in BFR in tibias at 8 weeks of age. These results indicate that deletion of Bmpr1a in differentiated osteoclasts increases osteoblastic bone formation, thus suggesting that BMPR1A signaling in osteoclasts regulates coupling to osteoblasts by reducing bone-formation activity during bone remodeling. (C) 2011 American Society for Bone and Mineral Research.

DOI： 10.1002/jbmr.477

Web of Science

PubMed

researchmap

Language：English   Publisher：INFORMA HEALTHCARE  

The treatment of osteoporosis has been a critical issue in today&apos;s medical situation. Various therapeutic agents and strategies have been investigated and applied, and have proven successful in the treatment of osteoporosis. However, some concerns still remain, such as the adverse effects of such treatments. From this point of view, a search for novel therapeutic targets, such as Fas signaling, remains important.

DOI： 10.1517/14728222.2011.600690

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CELL PRESS  

Endocrine therapies for breast cancer that target the estrogen receptor (ER) are ineffective in the 25%-30% of cases that are ER negative (ER-). Androgen receptor (AR) is expressed in 60%-70% of breast tumors, independent of ER status. How androgens and AR regulate breast cancer growth remains largely unknown. We find that AR is enriched in ER- breast tumors that overexpress HER2. Through analysis of the AR cistrome and androgen-regulated gene expression in ER-/HER2+ breast cancers we find that AR mediates ligand-dependent activation of Wnt and HER2 signaling pathways through direct transcriptional induction of WNT7B and HER3. Specific targeting of AR, Wnt or HER2 signaling impairs androgen-stimulated tumor cell growth suggesting potential therapeutic approaches for ER-/HER2+ breast cancers.

DOI： 10.1016/j.ccr.2011.05.026

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATURE PUBLISHING GROUP  

Reversible histone methylation and demethylation are highly regulated processes that are crucial for chromatin reorganization and regulation of gene transcription in response to extracellular conditions. However, the mechanisms that regulate histone-modifying enzymes are largely unknown. Here, we characterized a protein kinase A (PKA)-dependent histone lysine demethylase complex, PHF2-ARID5B. PHF2, a jmjC demethylase, is enzymatically inactive by itself, but becomes an active H3K9Me2 demethylase through PKA-mediated phosphorylation. We found that phosphorylated PHF2 then associates with ARID5B, a DNA-binding protein, and induce demethylation of methylated ARID5B. This modification leads to targeting of the PHF2 ARID5B complex to its target promoters, where it removes the repressive H3K9Me2 mark. These findings suggest that the PHF2 ARID5B complex is a signal-sensing modulator of histone methylation and gene transcription, in which phosphorylation of PHF2 enables subsequent formation of a competent and specific histone demethylase complex.

DOI： 10.1038/ncb2228

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC ADVANCEMENT SCIENCE  

In immune cells, the positive role of the extracellular signal-regulated kinase (ERK) signaling pathway in cell cycle progression and survival is well established; however, it is unclear whether ERK signaling plays a role in cell differentiation. Here, we report that ERKs are essential for the differentiation of B cells into antibody-producing plasma cells and that ERKs induce the expression of Prdm1, which encodes Blimp-1, a transcriptional repressor and "master regulator" of plasma cell differentiation. Transgenic mice with conditional deletion of both ERK1 and ERK2 in germinal center (GC) B cells lacked plasma cells differentiated after GC formation, and memory B cells from these mice failed to differentiate into plasma cells. In addition, ERK1- and ERK2-deficient B cells exhibited impaired Prdm1 expression upon stimulation with antibody against CD40 in the presence of interleukin-4; conversely, enforced expression of Prdm1 in ERK1- and ERK2-deficient B cells restored the generation of plasma cells. Thus, our study suggests that cytokines stimulate ERKs to induce the production of Blimp-1 and that ERKs thereby contribute to the process of cellular differentiation.

DOI： 10.1126/scisignal.2001592

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Prostate cancer development is associated with hyperactive androgen signaling. However, the molecular link between androgen receptor (AR) function and humoral factors remains elusive. A prostate cancer mouse model was generated by selectively mutating the AR threonine 877 into alanine in prostatic epithelial cells through Cre-ERT2-mediated targeted somatic mutagenesis. Such AR point mutant mice (ARpe-T877A/Y) developed hypertrophic prostates with responses to both an androgen antagonist and estrogen, although no prostatic tumor was seen. In prostate cancer model transgenic mice, the onset of prostatic tumorigenesis as well as tumor growth was significantly potentiated by introduction of the AR T877A mutation into the prostate. Genetic screening of mice identified Wnt-5a as an activator. Enhanced Wnt-5a expression was detected in the malignant prostate tumors of patients, whereas in benign prostatic hyperplasia such aberrant up-regulation was not obvious. These findings suggest that a noncanonical Wnt signal stimulates development of prostatic tumors with AR hyperfunction.

DOI： 10.1073/pnas.1014850108

Scopus

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：NATL ACAD SCIENCES  

Prostate cancer development is associated with hyperactive androgen signaling. However, the molecular link between androgen receptor (AR) function and humoral factors remains elusive. A prostate cancer mouse model was generated by selectively mutating the AR threonine 877 into alanine in prostatic epithelial cells through Cre-ERT2-mediated targeted somatic mutagenesis. Such AR point mutant mice (AR(pe-T877A/Y)) developed hypertrophic prostates with responses to both an androgen antagonist and estrogen, although no prostatic tumor was seen. In prostate cancer model transgenic mice, the onset of prostatic tumorigenesis as well as tumor growth was significantly potentiated by introduction of the AR T877A mutation into the prostate. Genetic screening of mice identified Wnt-5a as an activator. Enhanced Wnt-5a expression was detected in the malignant prostate tumors of patients, whereas in benign prostatic hyperplasia such aberrant up-regulation was not obvious. These findings suggest that a noncanonical Wnt signal stimulates development of prostatic tumors with AR hyperfunction.

DOI： 10.1073/pnas.1014850108

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL  

Multinucleation is indispensable for the bone-resorbing activity of mature osteoclasts. Although multinucleation is evident in mature osteoclasts and certain other cell types, putative regulatory networks among nuclei remain poorly characterized. To address this issue, transcriptional activity of each nucleus in a multinucleated osteoclast was assessed by detecting the distributions of nuclear proteins by immunocytochemistry and primary transcripts by RNA FISH. Patterns of epigenetic histone markers governing transcription as well as localization of tested nuclear receptor proteins appeared indistinguishable among nuclei in differentiated Raw264 cells and mouse mature osteoclasts. However, RNAPII-Ser5P/2P and NFATc1 proteins were selectively distributed in certain nuclei in the same cell. Similarly, the distributions of primary transcripts for osteoclast-specific genes (Nfatc1, Ctsk and Acp5) as well as a housekeeping gene (beta-tubulin) were limited in certain nuclei within individual cells. By fusing two Raw264 cell lines that stably expressed ZsGreen-NLS and DsRed-NLS proteins, transmission of nuclear proteins across all of the nuclei in a cell could be observed, presumably through the shared cytoplasm. Taken together, we conclude that although nuclear proteins are diffusible among nuclei, only certain nuclei within a multinucleated osteoclast are transcriptionally active.

DOI： 10.1111/j.1365-2443.2010.01441.x

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：TAYLOR & FRANCIS LTD  

Multinucleation is indispensable to the bone-resorbing activity of mature osteoclasts. Nevertheless, little is known about the regulatory networks among multinuclei in a single mature osteoclast. For this reason, we purified osteoclastic factors from the nuclear envelope by two-dimensional gel electrophoresis. Two annexin family proteins and ferritin light chain 1 protein were identified as osteoclastic candidates.

DOI： 10.1271/bbb.100280

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

What makes treatment choice for developmental dysplasia of the hips diagnosed after walking age difficult is the poor understanding of prereduction conditions that obstruct the reduction in spatial terms. To evaluate these problems, we employed subtraction three-dimensional imaging to search for the factors involved in intraarticular obstruction. On the basis of the findings of preoperative subtraction threedimensional imaging from computed tomography, we developed a new method, a minimum invasive arthroscopic reduction with limboplasty, for reduction of developmental dysplasia of the hips after walking age. The purposes of this report were to: (1) describe the technique of the arthroscopic procedure, and (2) evaluate our new method using radiographic parameters.
Ten patients with ten hips with developmental dysplasia after walking age treated by arthroscopic reduction with limboplasty were included in this study. The mean age of the patients at reduction was 22.6 months (range, 18.6-29.7 months); mean age at follow up was 7.2 years (range, 3.9-10.9 years); and mean follow up was 5.4 years (range, 1.7-9.0 years). These ten hips were evaluated using radiographic measurements.
Moderate or severe avascular necrosis of the femoral head was not observed. Two hips that had a spherical-shaped head with minimal residual height loss or coxa magna were classified as Kalamchi and MacEwen grade 1. Additional surgery had been performed for two hips classified as Severin group 4 during the course of follow up. These two hips were classified as Severin group 1 at final examination. One more hip was classified as Severin group 4 at final examination, and additional surgery was recommended. The remaining seven hips (70%) therefore obtained good evaluations by arthroscopic reduction with limboplasty alone.
We developed a new reduction method by using an arthroscopic procedure for the reduction of developmental dysplasia of the hips after walking age when this dysplasia failed to be reduced with nonoperative methods. The result of our new method is acceptable because good evaluations were obtained in 70% of hips 5.4 years after reduction by our new method alone.

DOI： 10.1007/s00776-010-1497-6

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Effective therapies for the regeneration of large osteochondral defects are still lacking; however, various approaches have been used. We evaluated the efficacy of Escherichia coli-derived dimeric recombinant human BMP-2 (E-rhBMP-2) for the repair of large osteochondral defects in a rabbit model. Osteochondral defects made in the femoral patellar groove of the knee were treated by transplanting gelatin sponges onto which no or various doses of E-rhBMP-2 were loaded. The outcomes were compared with those of an untreated control group four, 12 and 24 weeks after transplantation. At early time points, the cartilage tissue was repaired in a dose-dependent manner, and bone repair was accelerated in the defects treated with high doses of E-rhBMP-2. At 24 weeks, the repair of cartilage tissue was better with E-rhBMP-2 treatment, even at low doses, than without E-rhBMP-2 treatment. Our findings suggest that the use of E-rhBMP-2 improves and accelerates the repair of osteochondral defects in a rabbit model.

DOI： 10.1007/s00264-009-0818-x

Web of Science

PubMed

researchmap

Language：English   Publisher：OXFORD UNIV PRESS INC  

The osteoprotective action of estrogen in women has drawn considerable attention because estrogen deficiency-induced osteoporosis became one of the most widely spread diseases in developed countries. In men, the significance of estrogen action for bone health maintenance is also apparent from the osteoporotic phenotype seen in male patients with genetically impaired estrogen signaling. Severe bone loss and high bone turnover, including typical osteofeatures seen in postmenopausal women, can also be recapitulated in rodents after ovariectomy. However, the expected osteoporotic phenotype is not observed in female mice deficient in estrogen receptor (ER)-alpha or -beta or both, even though the degenerative defects are clearly seen in other estrogen target tissues together with up-regulated levels of circulating testosterone. It has also been reported that estrogens may attenuate bone remodeling by cell autonomous suppressive effects on osteoblastogenesis and osteoclastogenesis. Hence, the effects of estrogens in bone appear to be complex, and the molecular role of bone estrogen receptors in osteoprotective estrogen action remains unclear. Instead, it has been proposed that estrogens indirectly control bone remodeling. For example, the enhanced production of cytokines under estrogen deficiency induces bone resorption through stimulation of osteoclastogenesis. However, the osteoporotic phenotype without systemic defects has been recapitulated in female (but not in male) mice by osteoclast-specific ablation of the ER alpha, proving that bone cells represent direct targets for estrogen action. An aberrant accumulation of mature osteoclasts in these female mutants indicates that in females, the inhibitory action of estrogens on bone resorption is mediated by the osteoclastic ER alpha through the shortened lifespan of osteoclasts. (Molecular Endocrinology 24: 877-885, 2010)

DOI： 10.1210/me.2009-0238

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

Etanercept (ETN), which is a recombinant human soluble tumor necrosis factor (TNF) receptor that inhibits TNF activity, is effective in the treatment of rheumatoid arthritis. We investigated the effect of ETN on recombinant human bone morphogenetic protein-2 (rhBMP-2)-induced ectopic bone formation in vivo. A block copolymer composed of poly-d,l-lactic acid with random insertion of p-dioxanone and polyethylene glycol (PLA-DX-PEG polymer) was used as the delivery system. Polymer discs (6 mm, 30 mg) containing 5 mu g rhBMP-2 were implanted into the left dorsal muscle pouch of mice (n = 50). In the systemic administration groups (n = 5 per group), ETN was subcutaneously injected (25 mg/human = 12.5 mu g/mouse) twice per week in a dose-dependent manner (placebo, 12.5 x 10(-3), 12.5 x 10(-1), 12.5, 125 mu g), whereas a single dose of ETN (placebo, 12.5 x 10(-3), 12.5 x 10(-1), 12.5, 125 mu g) was embedded in each rhBMP-2 polymer disc in the local administration groups (n = 5 per group). Three weeks after implantation, the mice were killed and the implants were analyzed. Implants in the optimally dosed groups had increased radiodensity, which was consistent with a significant increase in bone mineral content of the ossicles. Bone histomorphology revealed a significant increase in bone volume/total volume, number of osteoblasts, osteoblast surface/bone surface, and a significant decrease in the number of osteoclasts, osteoclast surface/bone surface in the optimal dosed systemic and locally administered groups. These data suggest that the optimal dose of ETN, administered either systemically or locally, enhanced the bone-inducing capacity of BMP with no apparent adverse systemic effects.

DOI： 10.1007/s00774-009-0127-x

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

Recombinant human bone morphogenetic protein (rhBMP) is a promising therapeutic cytokine for the induction of bone formation, but a weak response in humans remains a major hurdle in its therapeutic application. We have previously reported an rhBMP-2-induced increase in the bone mass of mice receiving systemic rolipram, a specific inhibitor of phosphodiesterase-4. To overcome the side effects of systemic administration of rolipram, we examined the effects of its local release. Polyethylene glycol discs were used as a delivery system. The discs were impregnated with rhBMP-2 and rolipram and implanted into the dorsal muscle pouches in mice. Bone formation was assessed by measuring the bone mineral content (BMC) of the formed bone. First, to determine the optimal dose of rolipram, we added 0-5000 nmol rolipram and 5 mu g rhBMP-2 to the pellets and found that 500 nmol rolipram was the most effective concentration for inducing bone formation after 4 weeks. Second, to examine the time course of bone formation, we implanted 5 mu g rhBMP-2 with 0 or 500 nmol rolipram and killed mice 5, 7, 10, 14, or 21 days after implantation. Bone formation was accelerated in the rolipram group. Finally, to determine the rolipram-induced increase in the effect of BMP, BMC obtained after treatment with 5 mu g rhBMP-2 and 500 nmol rolipram was compared with that obtained after treatment with 5-9 mu g rhBMP-2 without rolipram, 4 weeks after implantation. The results indicated that 500 nmol rolipram enhanced the effect of rhBMP-2 by almost 1.5-fold. In summary, locally released rolipram enhanced the capacity of rhBMP-2 to induce bone formation, an effect previously reported with systemic administration. These findings may decrease the cost and increase the efficacy of rhBMP-2 treatment.

DOI： 10.1007/s00774-009-0103-5

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：BLACKWELL PUBLISHING  

Mature osteoclasts are multinuclear, macrophage-like cells derived from hematopoietic stem cells in the bone marrow. Several transcription factors regulating osteoclast differentiation have been identified. However, the molecular basis of transcriptional regulation in osteoclasts at epigenetic levels is largely unknown. In fact, no osteoclast-specific transcriptional co-regulators have been characterized. Recently, selective ablation of estrogen receptor alpha (ER alpha) in mature osteoclasts derived from female mice (ER alpha(Delta oc)/(Delta oc)) exhibited trabecular bone loss due to induced apoptosis via upregulated expression of Fas ligand mRNA. In general, the component composition of the ER alpha-associated coactivator complex and its expression levels are distinct among tissues. However, ER alpha-transcriptional co-regulators in mature osteoclasts remain unclear. In the present study, we achieved large-scale cultivation of mature, multinucleated osteoclasts and established a purification system for ER alpha-associated proteins. In addition to co-regulators previously found in other ERa target cells, several unexpected factors were found such as CAP-H. The mRNA expression level of CAP-H was high during osteoclast differentiation. These results demonstrate the existence of osteoclast-specific transcriptional co-regulators supporting ER alpha function.

DOI： 10.1111/j.1749-6632.2009.05215.x

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Bone morphogenetic proteins (BMPs) were originally identified as osteoinductive proteins. With cloning of BMP genes, studies of BMPs and their clinical application have advanced. However, with increasing clinical applications, drug delivery systems and production costs have become more important issues. To address these issues, we asked whether E. coli-derived rhBMP-2 (E-BMP-2)-adsorbed porous beta-TCP granules could achieve posterolateral lumbar fusion in a rabbit model similar to autogenous bone grafts. Lumbar spinal fusion masses were evaluated by 3-D computed tomography, mechanical testing, and histological analyses 8 weeks after surgery. By these measures E-BMP-2-adsorbed beta-TCP granules achieved lumbar spinal fusion in dose-dependent fashion in a rabbit model as well as autogenous bone graft. Our preliminary findings suggest E-BMP-2-adsorbed porous beta-TCP could be a novel, effective alternative to autogenous bone grafting for generating new bone and promoting regenerative repair of bone, and potentially utilizable in the clinical setting for treating spinal disorders.

DOI： 10.1007/s11999-009-0960-1

Web of Science

PubMed

researchmap

Language：English   Publisher：ELSEVIER IRELAND LTD  

Bone tissue protects and supports soft organs and maintains calcium homeostasis. Steroid sex hormones and fat-soluble vitamins play a pivotal role in regulation of bone homeostasis. turnover and remodeling. These molecules act as ligands of nuclear receptors, through which they control gene expression in bone cells, namely bone-forming osteoblasts, bone-resorptive osteoclasts and osteocytes. Significant advances in our understanding of nuclear receptor physiology have been achieved due to development of novel genetic manipulation approaches and generation of experimental animal models in which nuclear receptor genes were mutated in specific cell types. In this review, we summarized some aspects of recent progress in studies on molecular mechanisms of cell-specific action of nuclear hormone receptors in bone tissue. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.mce.2008.08.015

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)  

Estrogens play a key role in regulation of bone mass and strength by controlling activity of bone-forming osteoblasts and bone-resorbing osteoclasts. Cellular effects of estrogens are mediated predominantly by the action of estrogen receptor alpha (ERalpha). In earlier studies, ablation of the ERalpha gene in mice did not result in osteoporotic phenotypes due to systemic endocrine disturbance and compensatory effects of elevated levels of testosterone. Despite the relatively well-established effects in osteoblasts, little is known about the direct action of estrogen in osteoclasts. Development in the last decade of more sophisticated genetic manipulation approaches opened new possibilities to explore cell-specific roles of nuclear receptors in bone tissue. Recently, we have generated osteoclast-specific ERalpha gene knockout mice and shown that in vivo estrogens directly regulate the life span of mature osteoclasts by inducing the expression of pro-apoptotic Fas ligand (FasL). Inhibitory effects of estrogens on osteoclast function were further studied in vitro. We observed sufficiently detectable ERalpha expression in osteoclasts differentiating from primary bone marrow cells or RAW264 cells, although levels of ERalpha were decreasing during progression of the differentiation into mature osteoclasts. Treatment with estrogens led to reduction in expression of osteoclast-specific genes controlling bone resorption activity. However, estrogens did not affect the size of multinucleated osteoclasts or number of nuclei in a mature osteoclast. In conclusion, in osteoclasts, estrogens function to inhibit bone resorption activity and vitality rather than differentiation.

DOI： 10.1111/j.1749-6632.2009.04954.x

PubMed

researchmap

DOI： 10.1111/j.1749-6632.2009.04954.x

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

Noggin is a major extracellular antagonist to bone morphogenetic proteins (BMPs) which binds to BMPs and blocks binding of them to BMP-specific receptors and negatively regulates BMP-induced osteoblastic differentiation. In this study, we investigated the effect of noggin silencing by transfection of small interfering RNA (siRNA) on BMP-induced osteoblastic differentiation in vitro and ectopic bone formation in vivo induced by recombinant human BMP-2 (rhBMP-2). Noggin mRNA expression was up-regulated in response to rhBMP-2 in C2C12 cells, a myoblastic cell line, in dose- and time-dependent fashion as determined by real-time RT-PCR assay. Silencing of noggin expression by transfection of noggin siRNA suppressed BMP-stimulated noggin expression, resulting in acceleration of BMP-induced osteoblastic differentiation. For in vivo noggin silencing, siRNA was injected locally into back muscles and transfected into local cells by electroporation, where rhBMP-2-retaining (5 mu g) collagen disks had been surgically placed. The implants were harvested at 2 weeks after surgery from experimental and control group mice and analyzed by radiological and histological methods. As a result, bone mineral content of ossicles ectopically induced by rhBMP-2 was significantly increased by silencing of noggin. Our findings suggest that silencing of noggin enhances the osteoblastic differentiation of BMP-responding cells in vitro and new bone formation induced by rhBMP-2 in vivo by eliminating negative regulation of the effects of BMP. RNA interference might be useful for intensifying the effects of BMP in promoting new bone (callus) formation in repair of damaged bone.

DOI： 10.1007/s00774-009-0054-x

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

One problem associated with clinical application of CHO-derived recombinant human bone morphogenetic protein (C-BMP-2) is its high cost due to the need for use of high doses. To solve this problem, Escherichia coli-derived BMP-2 (E-BMP-2) has been examined using the technique of molecular unfolding and refolding. However, it is unclear whether the characteristics of E-BMP-2 are appropriate for clinical application. In this study, we examined the biological activity of E-BMP-2 and its heat tolerance in in vitro and in vivo systems. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) confirmed the high purity of E-BMP-2. E-BMP-2-induced alkaline phosphatase expression in osteoprogenitor cells (C2C12, ST2, and primary murine calvarial osteoblast cells) was dose-dependent, and consistently elicited ectopic new ossicles of significant size in mice, also in dose-dependent fashion. In addition, E-BMP-2 induced phosphorylation of Smad1/5/8 and mRNA expression of osteoblastic differentiation markers to the same extent as C-BMP-2. On the other hand, when E-BMP-2 was exposed to increasing heat over time, its bone-inducing capacity was maintained until reaching 70A degrees C for 2 h or 90A degrees C for 15 min. Thus, E-BMP-2 will exhibit a decrease in activity with the sterilization procedures required prior to use in surgery. These findings indicate that the biological capacity and heat stability of E-BMP-2 are almost equivalent to those of currently available C-BMP-2, and suggest that E-BMP-2 might, thus, solve current problems of cost impeding routine clinical use of rhBMP-2.

DOI： 10.1007/s00774-009-0040-3

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Intermittent subcutaneous injections of parathyroid hormone (PTH) increase bone mass in a variety of animal models and humans. The anabolic actions of PTH on osteogenic cells are mainly mediated through the protein kinase A (PKA) signaling pathway via PTH receptor I (PTHR1). We have already reported 3&apos;, 5&apos;-cyclic adenosine monophosphate (cAMP)/PKA-mediated enhancement of bone morphogenetic protein (BMP) signaling. Herein, we focused on the involvement of PTH in BMP signaling pathways in the MC3T3-E1 mouse osteoblastic cell line, to elucidate a potential mechanism of the anabolic actions of PTH on bone formation. Elevation of intracellular cAMP level in MC3T3-E1 cells by addition of PTH (10(-7) M) to culture media was transient without significant effect on biological actions of BMP. Cyclic addition of PTH (10 cyclic additions of 10(-8) M PTH at 3-min intervals) maintained a high intracellular cAMP level for about 2 h and mRNA expression and enzymatic activity of alkaline phosphatase (ALP) by BMP was enhanced by this addition. Relative luciferase expression assay in MC3T3-E1 cells using the Id1 promoter, an early response gene to BMPs, enhanced elevation of transcriptional activity in response to recombinant human BMP-2 by concomitant addition of PTH and BMP. Furthermore, cyclic PTH treatment significantly further suppressed BMP-induced inhibitory Smad6 expression. H89 (PKA inhibitor) almost completely abolished PTH actions on BMP signaling. IBMX (phosphodiesterase inhibitor) enhanced PTH actions. These results suggest that PTH enhances BMP signaling when PTH-induced intracellular cAMP level is maintained for a few hours, accelerating BMP actions to promote osteoblastic function and anabolic actions of new bone formation. (C) 2009 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2009.01.370

Web of Science

PubMed

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

PubMed

researchmap

Language：English   Publisher：SPRINGER TOKYO  

The multifarious functions of sex steroid receptors include a role as regulatory factors for bone and mineral metabolism in vivo. These functions are more complex than originally assumed. The finding of nuclear receptors in osseous tissue alludes to the existence of novel indirect and direct functions of bone tissue beyond skeletal support, hematopoiesis, and calcium homeostasis. Cell-specific gene targeting approaches are an extremely important technology for future studies that will need to be conducted to fully understand the molecular mechanisms underlying bone formation and metabolism.

DOI： 10.1007/s00774-008-0021-y

Web of Science

PubMed

researchmap

Language：Japanese   Publishing type：Research paper (scientific journal)  

Scopus

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：INFORMA HEALTHCARE  

Background and purpose Osteochondral defects have a limited capacity for repair. We therefore investigated the effects of tumor necrosis factor (TNF) signal blockade by etanercept (human recombinant soluble TNF receptor) on the repair of osteochondral defects in rabbit knees.
Material and methods Osteochondral defects (5 mm in diameter) were created in the femoral patellar groove in rabbits. Soon after the procedure, a first subcutaneous injection of etanercept was performed. This single injection or, alternatively, 4 injections in total (twice a week for 2 weeks) were given. Each of these 2 groups was divided further into 3 subgroups: a low-dose group (0.05 mu g/kg), an intermediate-dose group (0.4 mu g/kg), and a high-dose group (1.6 mu g/kg) with 19 rabbits in each. As a control, 19 rabbits were injected with water alone. The rabbits in each subgroup were killed 4 weeks (6 rabbits), 8 weeks (6 rabbits), or 24 weeks (7 rabbits) after surgery and repair was assessed histologically.
Results Histological examination revealed that the natural process of repair of the osteochondral defects was promoted by 4 subcutaneous injections of intermediate-dose etanercept and by 1 or 4 injections of high-dose etanercept at the various time points examined postoperatively (4, 8, and 24 weeks). Western blot showed that rabbit TNF alpha had a high affinity for etanercept.
Interpretation Blocking of TNF by etanercept enabled repair of osteochondral defects in rabbit knee. Anti-TNF therapy could be a strategy for the use of tissue engineering for bone and cartilage repair.

DOI： 10.3109/17453670903350115

Web of Science

PubMed

researchmap

Language：English   Publisher：ELSEVIER IRELAND LTD  

DOI： 10.1016/j.jdermsci.2008.04.014

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

We present experimental results indicating involvement of cyclic AMP (cAMP)-mediated signaling in bone morphogenetic protein (BMP)-induced osteoblastic gene expression at the transcriptional level by luciferase activity assay in C2C12 cells using the promoter sequence of the Id1 gene, an early-response gene to BMPs, which contains both a BMP-responsive element (BRE) and a cAMP-response element (CRE). In cells transfected with luciferase gene driven by wild-type Id1 promoter, treatment with BMP-4 increased luciferase expression, which was further enhanced by the addition of dibutyryl cAMP (dbcAMP). This dbcAMP-enhanced luciferase expression was significantly suppressed when the CRE site in the Id1 promoter was replaced by mutated CRE or endogenous CRE-binding protein (CREB) was knocked down by transfection of CREB RNAi. Pretreatment of cells with protein kinase A (PKA) inhibitor, H89, also dramatically reduced dbcAMP-enhanced luciferase expression. Immunoprecipitation assay showed phosphorylated-Smad1/5/8, phosphorylated-CREB, and CREB-binding protein (CBP) formed the transcriptional complex. These data indicate that cAMP-PKA/CREB/CRE signaling potentially enhances BMP-induced transcription through the BRE in the promoter of the BMP-responsive gene through a PKA-mediated pathway.

DOI： 10.1007/s00774-008-0850-8

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

The promotion of osteoblastic differentiation by bone morphogenetic proteins (BMPs) is accelerated by chemical compounds that increase the intracellular concentration of cyclic 3',5'-adenosine monophosphate (cAMP). cAMP is synthesized from adenosine triphosphate (ATP) by adenyl cyclase and degraded by phosphodiesterase (PDE) family enzymes. Inhibition of PDEs leads to prolonged accumulation of cAMP within cells and Camp-mediated reactions. Rolipram, a specific inhibitor of PDE4, is a compound effective in inducing osteoblastic differentiation. Four PDE4 family members are transcribed from four distinct genes (4A, 4B, 4C, and 4D). Expression of PDE4A and PDE4D has been observed in osteoblastic cells. We identified PDE4D splicing variants that expressed in ST2 or primary calvarial osteoblasts by rapid amplification of the 5'-ends of cDNA when they were cultured with BMP. PDE4D9 mRNA was identified from ST2, and PDE4D1 and -4D2 mRNAs were identified from primary calvarial osteoblasts. Expression of these three variants of PDE4D mRNA was found in ST2, MC3T3-E1, C3H10T1/2, C2C12, and primary calvarial osteoblasts by RT-PCR, but not PDE4D1 or -4D2 in ST2 or PDE4D2 in MC3T3-E1. Expression of these three variants was detectable in brain, heart, lung, liver, kidney, placenta, and femur, and was thus ubiquitous. Purified recombinant PDE4D9 protein exhibited phosphodiesterase activity, which degraded cAMP to AMP, and this activity was inhibited by rolipram. These findings suggest that PDE4D1, -2, and -9 play some roles in bone formation.

DOI： 10.1007/s00774-007-0803-7

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER ASSOC ADVANCEMENT SCIENCE  

Cathepsin K was originally identified as an osteoclast- specific lysosomal protease, the inhibitor of which has been considered might have therapeutic potential. We show that inhibition of cathepsin K could potently suppress autoimmune inflammation of the joints as well as osteoclastic bone resorption in autoimmune arthritis. Furthermore, cathepsin K-/- mice were resistant to experimental autoimmune encephalomyelitis. Pharmacological inhibition or targeted disruption of cathepsin K resulted in defective Toll- like receptor 9 signaling in dendritic cells in response to unmethylated CpG DNA, which in turn led to attenuated induction of T helper 17 cells, without affecting the antigen- presenting ability of dendritic cells. These results suggest that cathepsin K plays an important role in the immune system and may serve as a valid therapeutic target in autoimmune diseases.

DOI： 10.1126/science.1150110

Web of Science

PubMed

researchmap

Language：Japanese   Publisher：日本皮膚科学会-大阪地方会・京滋地方会  

researchmap

Language：Japanese   Publisher：(公社)日本生化学会  

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Bone morphogenetic proteins (BMPs) were originally isolated based on their ability to induce ectopic cartilage and bone formation. The agents to promote the local bone fori-nation with BMP would be beneficial to promote bone repair and to shorten the treatment period. For this purpose, we have examined ONO-4819, which is a prostaglandin (PG) E-2 EP4 receptor selective agonist (EP4A), as a positive modulators for the efficacy of BMPs. In our previous study, the systemic and local (with biodegradable synthetic polymers) administration of EP4A led to a significant augmentation of ossicle mass. But the mechanisms how EP4A accelerates the BMP-mediated bone formation are still unknown. In this study, we have examined how EP4A facilitates the BMP signaling using in vitro system with pluripotent stromal cell line, ST2. The mRNA expressions of Osterix and ALP (a marker enzyme of osteoblastic differentiation) and enzymatic activity of ALP in the ST2 cells were elevated significantly by BMP treatment. This elevation was further elevated by addition of the EP4A. The accelerated BMP action by the EP4A was abolished by pretreatment with PKA inhibitor.
This study suggests that ONO-4819 accelerates BMP-induced osteoblastic differentiation of ST2 cells by stimulating the commitment for ostcoblastic lineage. Thus PKA signaling pathway would be the main intracellular signaling pathway of the EP4 for the anabolic effect of bone and mineral metabolisms. (C) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2007.06.013

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CELL PRESS  

Estrogen prevents osteoporotic bone loss by attenuating bone resorption; however, the molecular basis for this is unknown. Here, we report a critical role for the osteoclastic estrogen receptor alpha (ER alpha) in mediating estrogendependent bone maintenance in female mice. We selectively ablated ER alpha in differentiated osteoclasts (ER alpha(Delta Oc/Delta Oc)) and found that ER alpha(Delta Oc/Delta Oc) females, but not males, exhibited trabecular bone loss, similar to the osteoporotic bone phenotype in postmenopausal women. Further, we show that estrogen induced apoptosis and upregulation of Fas ligand (FasL) expression in osteoclasts of the trabecular bones of WT but not ER alpha(Delta Oc/Delta Oc) mice. The expression of ER alpha was also required for the induction of apoptosis by tamoxifen and estrogen in cultured osteoclasts. Our results support a model in which estrogen regulates the life span of mature osteoclasts via the induction of the Fas/FasL system, thereby providing an explanation for the osteoprotective function of estrogen as well as SERMs.

DOI： 10.1016/j.cell.2007.07.025

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

Isolated fracture of the calcaneal apophysis is a rare injury in children and adolescents. In this study, we report on a case of a displaced calcaneal apophyseal avulsion fracture in a child treated with open reduction and internal fixation, as well as a review of the literature. A 9-year-old female child presented to the senior surgeon complaining of acute heel pain after a gymnastic injury. She was diagnosed with a displaced, isolated fracture of the proximal calcaneal apophysis for which she underwent open reduction and internal fixation. On the magnetic resonance imaging (MRI) examination, we could diagnose that her injury was not chronic but acute because there was no change of intensity in the metaphyseal area. A combination of bioabsorbable suture tacks and pins was used to anatomically fix the fragment using the tension band wiring technique. At 2 years and 6 months follow-up, she had full range of motion, complete return of strength. We report here on the successful surgical treatment and the first case evaluated by MRI of an avulsion fracture of the calcaneal apophysis in a child.

DOI： 10.1007/s00402-007-0297-8

Web of Science

PubMed

researchmap

DOI： 10.1016/j.cell.2007.07.025

J-GLOBAL

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor (TGF)-beta superfamily, and some display potent osteogenic activity both in vivo and in vitro. The BNIP signaling cascade involving BMP receptors at the cell membrane and intracellular messengers (Smads) has been elucidated, but the regulatory mechanisms of BMP signaling have not been clarified. We previously found that pentoxifyline (PeTx), a nonspecific inhibitor of phosphodiesterase (PDE), and rolipram, a PDE-4-specific inhibitor, enhance BMP-4-induced osteogenic differentiation of mesenchymal cells, probably through the elevation of intracellular cyclic adenosine monophosphate (cAMP) accumulation and modulation of BMP signaling pathways as enhanced BMP-4 action was reproduced by addition of dibutylyl-cAMP (dbcAMP). However, the precise mechanisms underlying the enhancing effects of those agents on BMP signaling were not completely revealed. As already reported, BMPs utilize a specific intracellular signaling cascade to target genes via R-Smads (Smad1,5,8), Co-Smad (Smad4) and I-Smads (Smad6,7). One possibility for cAMP-mediated effects on BMP signaling might be suppression of I-Smads expression since these proteins form a negative feedback loop in BMP signaling. To examine this possibility, changes in I-Smad (Smad6) expression on addition of dbcAMP or PeTx were examined in a bone-marrow-derived osteogenic cell line (ST2). Alkaline phosphatase activity in ST2 cells was consistently induced by BMP-4 treatment (300 ng/ml), and Smad6 mRNA expression was also induced by BMP-4 treatment. Although concurrent treatment of ST2 cells with BMP-4 and dbcAMP elicited further activation of alkaline phosphatase, addition of dbcAMP reduced BMP-4-induced Smad6 expression in a dose-dependent manner. Furthermore, detection of phosphorylated Smad1/5/8 on Western blotting analysis was prolonged, suggesting prolonged kinase activity of BNIP receptors through suppressed expression of Smad6. Elevated intracellular cAMP might thus enhance BMP signaling by suppressing Smad6 induction and prolonging intracellular BMP signaling. (c) 2005 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bone.2005.08.006

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER TOKYO  

This study was designed to investigate effects of heat on the bone-inducing activity of recombinant human bone morphogenetic protein (rhBMP)-2. rhBMP-2 samples were heated at 50, 70, 90, or 100 degrees C for 15 min, or 1, 2, 4, or 8 h, or autoclaved at 120 degrees C for 15 min. The bone-inducing activity of the rhBMP-2 before and after heating was assayed in in vivo and in vitro systems. For the in vivo assay, 5 mu g rhBMP-2 samples were impregnated into porous collagen disks (6 mm in diameter, 1 mm thickness), freeze dried, and implanted into the back muscles of ddY mice. Three weeks later, the implant was harvested from the host and examined for ectopic new bone tissue by radiography. The new bone mass was quantified by single-energy X-ray absorptiometry. The in vitro activity of the rhBMP-2 was assayed by adding the BMP sample at a concentration of 100 ng/ml to cultures of MC3T3-E1 cells. After 48 h, the alkaline phosphatase activity was measured. After heating at 50 or 70 degrees C, no significant reduction in bone-inducing activity was noted in either in vivo or in vitro assay systems unless the protein was exposed to sustained heat at 70 degrees C for 8 h, based on in vitro assay data. However, heating above 90 degrees C and for longer periods led to a decrease in the biological activity of the rhBMP-2 in a time-and temperature-dependent manner. rhBMP-2 was rendered inactive when exposed to temperatures at or in excess of 120 degrees C.

DOI： 10.1007/s00774-005-0623-6

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER SOC BONE & MINERAL RES  

Hepatocyte growth factor (HGF) is activated and the expression of BMP receptors (BMPRs) is induced around the fracture site during the early phase of fracture repair. HGF facilitates the expression of BMPRs in mesenchymal cells. This study suggests that HGF contributes to fracture repair by inducing the expression of BMPRs.
Introduction: The precise mechanisms that control the upregulation of BMP, BMPRs, and other molecules involved in bone repair are not completely understood. In this study, we hypothesized that HGF, activated through the action of thrombin on the HGF activator, may enhance BMP action through the local induction of BMP or BMPRs.
Materials and Methods: Callus samples from tibial fractures in mice were harvested for immunohistochemical analysis of HGF and phosphorylated c-Met, for in situ hybridization of BMPRs, and for real-time RT-PCR analysis for the expression of HGF, c-Met, and BMPRs. To study the changes in gene expression of BMPRs in response to HGF, C3H10T1/2 cells were cultured with or without HGF and harvested for real-time RT-PCR and for Western blot analysis. To evaluate the contribution of HGF to the biological action of BMP2, C3H10T1/2 cells and primary muscle-derived mesenchymal cells were precultured with HGF and cultured with BMP2. In addition, the expression of the luciferase gene linked to the Id1 promoter containing the BNIP responsive element and alkaline phosphatase (ALP) activity were assayed.
Results: Positive immunostaining of HGF and phosphorylated c-Met was detected around the fracture site at 1 day after the fracture was made. mRNA expression of BMPRs was increased 1 day after fracture and localized in mesenchymal cells at the fracture site. From an in vitro study, the expression of mRNA for BMPRs was elevated by treatment with HGF, but the expression of BMP4 did not change. Western blot analysis also showed the upregulation of BMPR2 by HGF treatment. The results from the luciferase and ALP assays indicated increased responsiveness to BMPs by treating with HGF.
Conclusions: This study indicates that HGF is activated and expressed at the fracture site and that HGF induces the upregulation of BMPRs in mesenchymal cells. Furthermore, HGF may facilitate BMP signaling without altering the expression of BMP molecules.

DOI： 10.1359/JBMR.050607

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

Recombinant human bone morphogenetic protein (rhBMP)-2 in a block copolymer composed of poly-D,L-lactic acid with randomly inserted p-dioxanone and polyethylene glycol (PLA-DX-PEG) as a carrier and porous beta-tricalcium phosphate (beta-TCP) blocks were used to generate a new fully absorbable osteogenic biomaterial. The bone regenerability of the rhBMP-2/PLA-DX-PEG/ beta-TCP composite was studied in a critical-sized rabbit bone defect model. In an initial study, a composite of PLA-DX-PEG (250mg) and beta-TCP (300 mg) loaded with or without rhBMP2 (50 mu g) was implanted into a 1.5 cm intercalated bone defect created in a rabbit femur. Defects were assessed by biweekly radiography until 8 weeks postoperatively. The bony union of the defect was recognized only in the BNIP-loaded group. To obtain further data on biomechanical and remodeling properties, another BNIP-loaded composites group was made and observed up to 24 weeks. All defects were completely repaired without residual traces of implants. Anatomical and mechanical properties of the repaired bone examined by histology, 3-dimensional CT (3D-CT) and mechanical testing were essentially equivalent to the nonoperated-on femur at 24 weeks. These experimental results indicate that fully absorbable rhBMP-2/PLA-DX-PEG/beta-TCP is a promising composite having osteogenicity efficient enough for repairing large bone defects. (c) 2005 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biomaterials.2005.01.054

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

The anabolic effects of prostaglandin E-2 on bone are effected through the activation of EP4, a G protein-coupled receptor. In the present study. we examined the effects of a prostanoid receptor-selective agonist (ONO-4819) in an experimental system of ectopic bone formation using recombinant human bone morphogenetic protein-2 (rhBMP-2). Collagen pellets containing rhBMP-2 were implanted onto the back muscles of mice and then treated with ONO-4819 administered every 8 h by subcutaneous injection. The ossicles elicited ectopically by rhBMP-2 in mice treated with 30 mug/kg ONO-4819 were significantly larger in size and had a higher bone mineral density and bone mineral content when compared to the controls. We also noted that the anabolic effect of ONO-4819 was seen only in the early phase of the rhBMP-2-induced bone-forming process. These experimental results indicate that the EP4 receptor agonist enhances the rhBMP-2-induced bone formation through a selective effect on early stage mesenchymal cells, which in turn may result in increased responsiveness of the host animals to rhBMP-2. (C) 2004 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.bbrc.2004.04.080

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：THIEME MEDICAL PUBL INC  

To evaluate the effect of cable nerve graft polarity, the bilateral common peroneal nerves in 12 rabbits were excised to create 20-mm nerve gaps. These gaps were repaired with cable grafts using three strands of 20-mm Ipsilateral sural nerves. In the left leg, the sural nerves were grafted with the original orientation. In the right leg, the nerve graft polarity was reversed 180degrees. Six months later, motor conduction velocities were evaluated, and the bilateral anterior tibial muscles and extensor digitorum longus muscles were measured. The nerves were harvested and analyzed histologically. Motor conduction velocity was 37.4+/-4.1 m/s in the reversed group, and 36.6+/-5.5 m/s in the control group. The weight of the muscles was 7.2+/-0.8 g in the reversed orientation, and 7.0+/-1.0 g in the original orientation. None of the differences was statistically significant. Histologically, the axon counts and the axonal density distal to the nerve graft also showed no differences between groups. The sural nerves used did not have a major branch and their diameter was almost the same throughout its length. Reversing nerve graft polarity of a cable graft did not affect nerve regeneration electrophysiologically or histologically.

DOI： 10.1055/s-2002-33323

Web of Science

PubMed

researchmap

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI IRELAND LTD  

We have investigated the actions of parathyroid hormone (PTH) and PTH-related peptide (PTHrP) on the bones of parathyroidectomized (PTX) rats by histomorphometric analysis. Miniosmotic pumps filled with either human PTH (hPTH)(1-34), hPTHrP(1-34) or vehicle were subcutaneously implanted on the backs of the rats. The peptides were continuously infused for 6 days at a rate of 15 nmole/kg/day. PTH and PTHrP exhibited similar hypercalcemic and hypophosphatemic actions on these PTX rats. No significant differences were noted in bone weight or calcium and phosphorus contents of the ashed bone among the 3 groups. By quantitative histomorphometric analysis, hPTH(1-34) and hPTHrP(1-34) were found similarly to enhance both bone formation and resorption. Peritrabecular fibrosis was observed only in the PTH-infused animals. PTHrP thus mimics the actions of PTH, but is not as effective in promoting mesenchymal cell proliferation along the bone trabeculae.

Web of Science

PubMed

researchmap

Total pages：203   Responsible for pages：193-198   Language：Japanese  

researchmap

Total pages：788   Responsible for pages：569-578   Language：English  

researchmap

Total pages：328   Responsible for pages：176-178   Language：Japanese  

researchmap

Total pages：355   Responsible for pages：104-109   Language：Japanese  

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：メディカルレビュー社  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：WILEY  

Web of Science

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：WILEY  

Web of Science

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：南江堂  

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：株式会社メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(一社)日本体力医学会  

researchmap

Language：English   Publisher：西日本泌尿器科学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：日本筋学会  

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (other)  

researchmap

Language：Japanese   Publisher：(株)日本メディカルセンター  

＜文献概要＞男性ホルモンであるアンドロゲンはアンドロゲン受容体に作用して,標的遺伝子の発現によって生理活性を発揮する.同時にアンドロゲンであるテストステロンは,女性ホルモンである17βエストラジオールの前駆体でもあり,性ステロイド生合成機構からも,アンドロゲンの作用を理解することが必要である.ヒトおよびマウスにおけるこれまでの研究から,アンドロゲンの骨量維持作用は,直接的および間接的な作用の総和であることを理解する必要がある.

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publishing type：Meeting report  

researchmap

Language：Japanese   Publisher：日本筋学会  

researchmap

Language：Japanese   Publisher：日本筋学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(株)羊土社  

超高齢社会を迎えた本邦における健康長寿の獲得は社会的課題である。要支援の主な原因となる転倒/骨折を予防するためには筋力強化が重要である。現在のところ、筋力強化に資する唯一の分子といえるアナボリックステロイドであるアンドロゲンは、筋力増強効果は認められるものの、心血管イベントを中心に多様な副作用リスクの増強も報告されている。アンドロゲン受容体遺伝子欠損マウスの解析から、アンドロゲンは直接的に骨格筋の筋質を制御すること、骨格筋外組織を介して間接的に筋量を制御することが明らかになりつつある。しかしながら詳細な分子メカニズムはいまだ大部分が不明であるため、サルコペニアなどの骨格筋疾患への新たな治療法開発のためには、さらなる研究が必要である。(著者抄録)

researchmap

Language：Japanese   Publisher：(一社)日本病理学会  

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)   Publisher：愛媛医学会  

超高齢社会を迎えた本邦において、健康長寿社会の実現のためには、要介護および要支援の原因となる運動器疾患の克服は社会的課題と言える。中でも骨粗鬆症患者数は1,300万人を超えると推計されている。先進国の中で本邦では未だに増加の一途を辿っている骨粗鬆症性骨折は、ADLのみならず生存率をも低下させる疾病である。骨粗鬆症の多くは閉経後骨粗鬆症であり、エストロゲン欠乏により惹起される高回転型骨代謝を伴う骨量減少を呈する。エストロゲンはエストロゲン受容体(ER:Estrogen Receptor)と結合して、その作用を発揮するため、閉経後骨粗鬆症の病態メカニズムの解析にはER機能の解析が不可欠である。過去に作出されたER遺伝子欠損マウスの解析から、エストロゲンには、骨組織以外の臓器/組織を介して骨量を維持する間接的骨量制御機構と骨組織に存在する3つの細胞種を標的とした直接的骨量制御機構が存在することが明らかとなってきた。つまり、エストロゲンによる骨量制御は、直接および間接的な多様な作用メカニズムの総和として理解することができる。(著者抄録)

researchmap

J-GLOBAL

researchmap

Language：Japanese  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publishing type：Research paper, summary (national, other academic conference)   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

本邦において約1,300万人と推定されている骨粗鬆症患者の大半は,閉経後骨粗鬆症である。閉経により女性ホルモンであるエストロゲンが欠乏することで,内分泌制御によるフィードバック機構やエストロゲンによる恒常性維持機構の破綻が主な原因となり,高回転型骨代謝を伴う骨吸収の亢進による骨量減少が惹起される。近年,エストロゲン受容体α遺伝子欠損マウスの解析を中心とした研究成果から,閉経後骨粗鬆症の分子メカニズムが明らかになりつつある。本稿では,エストロゲンによる直接的及び間接的な骨代謝制御機構について述べるとともに,エストロゲン代謝産物による骨代謝制御の可能性についても紹介したい。(著者抄録)

researchmap

Language：Japanese   Publisher：(一社)日本病理学会  

researchmap

Language：Japanese   Publisher：(株)医学書院  

性ステロイドホルモン受容体は,特異的なリガンドとの結合により転写因子として作用し,ゲノム全体での結合領域,遺伝子発現を制御する.近年の次世代型シーケンサの発展で,ゲノムワイド解析の大部分が,転写因子の結合領域(ChIP-seq)と遺伝子発現プロファイル(RNA-seq)の統合的解析により行われている.性ステロイドホルモン受容体の統合的ゲノムワイド解析は,さまざまな性ホルモン応答性疾患の治療標的となりうる分子の同定が可能となり,治療法開発への一助となることが期待されている.(著者抄録)

DOI： 10.11477/mf.1409208928

researchmap

J-GLOBAL

researchmap

J-GLOBAL

researchmap

Language：Japanese   Publisher：(株)南江堂  

researchmap

Language：Japanese   Publisher：日本組織細胞化学会  

researchmap

Language：Japanese  

J-GLOBAL

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

男性骨粗鬆症病態を理解するため,アンドロゲン受容体(AR)によるエピジェネティクス制御機構は重要な要素と言える。ARによるエピエジェネティクスには,ARの転写共役因子に含まれるエピエジェネティクス制御因子の役割が必須であり,中でもlysine-specific demethylase 1(LSD1)の作用機序について研究が進んでいる。本稿では,主に前立腺細胞において発見されたARによるエピジェネティクス制御と,共役因子であるLSD1の作用を中心に,ARに関連したエピジェネティクス制御因子について,近年の知見を踏まえて紹介する。(著者抄録)

researchmap

Language：Japanese  

researchmap

Other Link： http://search.jamas.or.jp/link/ui/2016366597

Language：Japanese   Publisher：(一社)日本病理学会  

researchmap

Language：Japanese   Publisher：(株)全日本病院出版会  

原発性骨粗鬆症の多くを占める閉経後骨粗鬆症の第一義的な原因は、卵巣機能低下による女性ホルモン:エストロゲンの血中濃度の低下である。つまり、エストロゲンには骨量を維持する作用があり、その恒常性維持の機構が破綻することでエストロゲン欠乏による骨粗鬆症が発症すると考えられる。かつて、エストロゲンは骨形成を促進する作用が中心であると考えられてきたが、近年の基礎研究の成果から、エストロゲンは、破骨細胞による骨吸収を抑制的に制御することにも大きな役割を担うこと明らかになってきた。なかでも、エストロゲンは、内分泌機構や免疫系などの骨以外の組織を介して骨吸収を制御する間接的作用と、骨組織に存在する破骨細胞や骨細胞などの細胞種に対する直接的作用を有し、多角的に骨量維持に寄与していることが明らかになりつつある。本稿では、エストロゲンによる骨量維持機構から閉経後骨粗鬆症の病態理解につながる基礎研究の知見を解説する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

生命科学におけるビッグデータは、次世代型シーケンサの出現により爆発的に進歩した。様々なシーケンスデータの代表例として、エピジェネティクスに関連したデータは、広くかつ詳細に多くの生命現象を解き明かす鍵となっている。本稿では、骨格関連細胞の分化へのビッグデータ応用の一例として、破骨細胞分化におけるDNase-seqデータからクロマチンリモデリング情報解析により、新規転写因子の同定につながる筆者らの研究を紹介する。骨格関連研究におけるビッグデータについては世界的な取り組みが行われており、今後ますます重要性が増していくものと考えられる。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

骨粗鬆症や変形性関節症など、骨、関節、筋肉などの運動器組織の疾患の罹患頻度には、大きな性差が存在する。疾患=恒常性の破綻と考えた場合、運動器組織の恒常性維持機構にも性差が存在すると考えられる。性差を担う要素には、性染色体と性ホルモンがあり、運動器疾患の多くが高齢者であることから性ホルモン欠乏が運動器疾患病態の一部を担っているとも言える。性ホルモンの作用は、核内受容体を介した標的組織での標的遺伝子の発現制御により発揮されることから、運動器組織における性ホルモン受容体の機能が重要である。本稿では、性ホルモン受容体遺伝子欠損マウスの解析から、骨・筋肉における標的遺伝子発現機構について最近の知見を含めて概説する。(著者抄録)

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

アンドロゲンは、性差を構築する一要因である性ホルモンの一つであり、男性(雄性)の構築に作用する。脳や内外性器の発達のみならず、運動器の性差にも重要な役割を果たしていると考えられているが、その詳細はいまだ不明な点が多い。近年のアンドロゲン受容体遺伝子欠損マウスの解析から、アンドロゲンによる骨代謝制御が、骨組織に対して直接的な作用によるものであることが明らかになりつつある。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)日本臨床社  

researchmap

Language：Japanese   Publisher：(株)日本メディカルセンター  

男性ホルモンであるアンドロゲンは,生殖器をはじめとした多くの器官における生体恒常性維持に必須のステロイドホルモンである.アンドロゲンの一種であるテストステロンの血中濃度が低下した場合,骨量減少が認められることからアンドロゲンによる骨量維持作用の存在が想定されるものの,その詳細は不明な部分が多い.近年の研究報告から,アンドロゲン受容体の骨組織での機能や転写調節におけるエピジェネティクス制御が明らかになりつつあり,骨粗鬆症治療の新たな標的となりうると考えられる.(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

閉経後骨粗鬆症の病態は、エストロゲン欠乏により惹起されることが明らかとなっている。しかしながら、閉経直前のエストロゲン濃度が保たれている状態でも骨量減少を認めることから、閉経により上昇する卵胞刺激ホルモン(FSH)による骨量制御が注目されている。基礎的研究から、FSHが直接的に破骨細胞形成を促進し、骨吸収を亢進させることで、骨量を負に制御することが報告されている一方で、FSHの強制発現マウスでは、卵巣機能依存的な骨量増加を認めるとの報告もあり、その骨量制御に対する作用は議論の余地がある。本稿では、最近の基礎的研究および臨床的研究報告から、FSHによる骨量制御について議論する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)羊土社  

骨代謝制御の1つの重要な要素に性ホルモンがあげられる。性ホルモンの欠乏により骨代謝異常が惹起されることはわかっていたものの、その機序については不明な点が多かった。しかし、近年の知見により、性ホルモンのなかでもエストロゲンが、免疫系や下垂体などのほかの組織を介して間接的に骨量維持に作用することや、骨組織に存在する3種の細胞種(破骨細胞、骨芽細胞、骨細胞)に直接的に作用して骨量維持を担っていることが明らかになってきた。性ホルモンによる骨量維持機構の理解は、新規薬剤開発の手がかりとなることが期待されている。(著者抄録)

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：WILEY-BLACKWELL  

Web of Science

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

閉経後骨粗鬆症は、エストロゲン欠乏により惹起される骨量減少である。骨粗鬆症治療を行う場合には、その病態を把握する必要があるが、エストロゲン欠乏による骨量減少機構の詳細なメカニズムは近年まで不明な点が多かった。しかしながら、遺伝子改変マウスを用いたエストロゲン受容体α(ERα)の生体内機能解析が進展したことにより様々な知見が報告され、閉経後骨粗鬆症病態の理解が進んできた。本稿では、エストロゲンによる骨組織内ERαを介した直接的骨量維持機構と多臓器を介した間接的骨量維持機構について、近年の新たな知見を紹介する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)メディカルドゥ  

先進諸国では,社会の高齢化が急速に進行しており,健康長寿の獲得が社会的急務といえる。健康長寿の獲得には,高齢者の運動機能低下や寝たきり生活の大きな要因となっている骨粗鬆症による骨折や関節リウマチ,変形性関節症などの運動器疾患を適切に予防・治療する必要がある。これらの疾患に対して,更なる新規治療法の開発が期待されているが,骨関節疾患における治療標的としてのエピジェネティクスの詳細については,大部分が不明であるといえる。本稿では,骨関節疾患の病態生理におけるエピジェネティクスに関する最近の知見について紹介する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)日本臨床社  

researchmap

Language：Japanese   Publisher：(株)南江堂  

エストロゲンはテストステロンからアロマターゼにより合成され,エストロゲン受容体と結合して,その作用を発揮する.エストロゲン欠乏により,骨吸収の亢進を伴う骨量低下が引き起こされる.エストロゲン欠乏による骨量低下は,エストロゲンによる間接的および直接的な骨量維持作用の総和の破綻により生じる.間接的作用は,免疫系細胞を介した炎症性サイトカインや卵胞刺激ホルモン(FSH)による骨吸収の増加などである.直接的作用は,エストロゲン受容体を介したFas ligandの遺伝子発現調節を伴う破骨細胞寿命調節などがある.ホルモン補充療法(HRT)は骨量増加・骨折予防効果を認めるものの,乳がんや血管イベントなど有害事象もある.選択的エストロゲン受容体作動薬(SERM)には,骨量増加・椎体骨折予防効果を認める.(著者抄録)

CiNii Books

researchmap

Other Link： http://search.jamas.or.jp/link/ui/2013155550

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：WILEY-BLACKWELL  

Web of Science

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：WILEY-BLACKWELL  

Web of Science

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

近年の目覚ましい骨代謝研究の発展から、骨代謝は、多臓器による複雑なネットワークにより制御されていることが明らかとなってきた。その要素の一つとして、内分泌制御機構の一部である性ホルモンによる骨代謝調節が挙げられる。主な性ホルモンとして、女性ホルモンであるエストロゲンと男性ホルモンであるアンドロゲンが知られている。性ホルモンの欠乏は骨量減少を誘導、その補充により、様々な有害事象が懸念されるものの、骨量回復を認めることから、性ホルモンが骨量維持に重要な役割を果たしていることは明らかである。本稿では、性ホルモンによる直接的および間接的骨代謝調節メカニズムについて概説する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)学研メディカル秀潤社  

CiNii Books

researchmap

Other Link： http://search.jamas.or.jp/link/ui/2013120509

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(有)科学評論社  

researchmap

Language：Japanese   Publisher：(株)先端医学社  

第2の遺伝暗号といわれるエピゲノム研究は、近年目覚ましいスピードで発展をとげている。しかしながら、骨代謝調節機構におけるエピゲノム制御はその大部分が不明である。骨吸収を担う破骨細胞の分化に必須であるRANKL(receptor activator of NF-κB ligand)の遺伝子発現は、ビタミンDをはじめとした種々の刺激により誘導されるが、その発現調節としてはプロモーター領域におけるDNAメチル化制御が明らかになりつつある。また、破骨細胞分化におけるヒストン修飾によるエピゲノム制御変動や、主要転写因子であるNFATc1(nuclear factor of activated T cells、cytoplasmic 1)を中心としたクロマチン構造変換によるエピゲノム制御因子の同定などが進みつつある。骨吸収における正と負のエピゲノム制御が解明されれば、骨関節疾患の新規治療法開発の一助となると期待される。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

破骨細胞は、造血幹細胞由来マクロファージ系細胞が、RANKLの刺激により複数の細胞が融合することで分化する多核巨細胞である。破骨細胞分化は、さまざまな分泌蛋白質や転写因子により厳密に制御されている。なかでも、NFATc1は破骨細胞分化の主要転写因子である。近年、転写因子群による遺伝子ネットワーク再構築の一端がエピジェネティック制御によって調節されると考えられているが、NFATc1転写制御機構をはじめ、破骨細胞の分化や成熟におけるエピジェネティック制御機構は未解明である。本稿では、われわれがこれまで、RAW264細胞を用いた生化学的な手法により検討した結果を踏まえ、破骨細胞におけるエピジェネティック制御機構、および制御因子群について概説する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

女性ホルモンであるエストロゲンと男性ホルモンであるアンドロゲンは、それぞれ核内受容体であるエストロゲン受容体(ER)とアンドロゲン受容体(AR)に結合し、標的遺伝子の発現調節を介して、その作用を発揮し、多様な恒常性の維持に寄与している。しかしながら、各種細胞においてERやARの細胞内挙動、DNAへの結合部位やその結合様式は多様である。近年、次世代型シーケンサーの出現により、目覚ましく発展しているゲノムワイド解析研究から、乳がんや前立腺がんにおいて、性ホルモン受容体の新たな機能や作用機序が明らかになりつつある。本稿では、ARに焦点を絞り、ゲノムワイド解析に関する最近の知見とともに、骨代謝領域への応用の試みについて紹介する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

エストロゲンによる骨量維持作用の重要性はよく知られている。その主な作用点は骨吸収抑制効果である。しかしながら、骨組織に多く存在する骨細胞への作用はいまだに不明である。われわれは、骨細胞ERα欠損マウスを作出、解析した結果、骨形成の低下を伴う骨量減少を雌マウスに認めた。これらの結果から、近年その特徴が明らかにされつつある骨細胞におけるエストロゲンの作用機序のみならず、骨代謝制御機構におけるエストロゲン作用のさらなる理解が深まることが期待される。(著者抄録)

researchmap

Language：Japanese   Publisher：(公社)日本ビタミン学会  

DOI： 10.20632/vso.86.1_42_2

researchmap

Language：Japanese   Publishing type：Book review, literature introduction, etc.  

Estrogen is well-known to play essential roles for maintenance of bone mass. Although its osteoprotective actions are mediated mainly through suppressing bone resorption, several reports has suggested that ERα/estrogen signal in osteocytes has some osteoprotective effects. For example, ERαis reported to be involved in adaptive response to loading which is thought to be sensed by osteocytes. Estrogen is also thought to be a viable factor for osteocytes. In addition, our group recently found that osteocytic ERαexhibited decreased bone mass, suggesting that osteocytic ERαexerts osteoprotective function. Also, functions of osteocyte itself have been characterized recently. These findings may lead to an understanding of estrogen actions on osteocytes and to a comprehensive understanding of estrogen actions on bone.

Scopus

PubMed

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(株)日本臨床社  

CiNii Books

researchmap

Other Link： http://search.jamas.or.jp/link/ui/2011236804

Language：Japanese   Publisher：近畿小児整形外科懇話会  

researchmap

Language：Japanese   Publisher：日本ビタミン学会  

CiNii Books

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER ASSOC CANCER RESEARCH  

DOI： 10.1158/1538-7445.AM2011-941

Web of Science

researchmap

Language：Japanese   Publisher：(公社)日本薬学会  

DOI： 10.14894/faruawpsj.47.3_203

CiNii Books

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(有)科学評論社  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：中部日本整形外科災害外科学会  

researchmap

Language：Japanese   Publisher：(有)医学の世界社  

CiNii Books

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

骨形成と骨吸収のバランスが維持されることで調節される骨組織は、閉経後骨粗鬆症ではエストロゲン欠乏によりそのバランスを失い、骨量減少に至る。エストロゲンを補填するHRT(hormone replacement therapy)では、さまざまな合併症を認めることから、SERM(selective estrogen receptor modulator)が開発、臨床応用され骨量回復に効果を発揮しているが、その詳細なメカニズムは不明な部分が多い。エストロゲン受容体αの遺伝子改変マウスやゲノムワイドなDNA結合部位の解析により、骨組織におけるエストロゲンおよびSERMの標的遺伝子がFasLであり、エストロゲン/SERMの骨量維持作用の一部が破骨細胞寿命の調節であることが明らかとなったが、より詳細なSERMの組織特異的作用メカニズムを解明することでより効果的なSERMの開発が期待される。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)北隆館  

性ステロイドホルモンをはじめとした低分子量脂溶性生理活性物質群をリガンドとする核内受容体群は、リガンド依存性DNA結合性転写制御因子として機能し、染色体構造調節を介して標的遺伝子群の発現を正負に転写レベルで制御する。一方性ステロイドホルモン作用には、性差が存在するものの、成人の骨代謝/骨量維持に必須なホルモンである。しかしながらこれら性ホルモンの骨組織内の作用点や、標的遺伝子等の分子機構は未だ不明な点が多い。これらの問題を解決するため、筆者等のグループでは、遺伝子破壊マウスを用いる事で、性ホルモン受容体群の高次機能を解析している。本稿では、これらマウスの骨変異を紹介したい。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

アンドロゲン(男性ホルモン)の骨組織に対する同化作用については、性差を超えて幅広い動物種で広く観察されている。アンドロゲンの同化作用は、骨組織のみならず、筋肉に対しても増強作用が認められているが、その作用点については不明である。本稿では、筆者らが作成した破骨細胞特異的男性ホルモン受容体欠損マウスの変異を述べることで、男性ホルモンの骨組織への作用点を考えたい。(著者抄録)

researchmap

Language：Japanese   Publisher：金原出版(株)  

researchmap

Language：Japanese   Publisher：(株)羊土社  

researchmap

Language：Japanese   Publisher：(株)先端医学社  

わが国をはじめ、先進諸国では高齢化が進み、高齢者の日常生活動作(activities of daily living:ADL)の向上・維持が重要な課題となっている。しかし、骨粗鬆症患者では、骨脆弱性に伴う易骨折性により、ADLを著しく低下させるのみならず、そのほかの合併症も引き起こす大きな問題となっており、種々の治療法が開発・臨床応用されつつある。なかでも、閉経後骨粗鬆症は、女性ホルモンであるエストロゲンの欠乏により惹起される病態であるが、エストロゲンを制御することでなぜ骨防御できるのか、その詳細な分子基盤は長い間不明な点が多かった。本稿では、エストロゲンによる間接的・直接的な骨量維持機構について、閉経後骨粗鬆症の病態の一部を説明しうるエストロゲン受容体(ER)αを中心に、最近の知見を概説する。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(公社)日本整形外科学会  

researchmap

Language：Japanese   Publisher：(公社)日本整形外科学会  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：ELSEVIER SCIENCE INC  

DOI： 10.1016/j.bone.2009.01.314

Web of Science

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：ELSEVIER SCIENCE INC  

DOI： 10.1016/j.bone.2009.01.112

Web of Science

researchmap

Language：Japanese   Publisher：(一社)日本臨床化学会  

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

運動器の中心の一つである骨組織は、外傷を中心とした損傷(=骨折)により、その支持機能を低下させた場合、著しいADL(activities of daily living)の低下を招く。現在、臨床の現場では骨折を予防する目的で、さまざまな治療が試みられ、大きな成果をあげているが、一定の割合で骨折は発生し、その治癒が奏功しない場合、大きな問題となる。また、骨折は自然治癒することが一般的であるが、その治癒過程を促進することができれば、より早期の社会復帰やADLの改善が認められるであろう。Uristにより提唱されたBMP(bone morphogenetic protein:骨形成因子)は、これらの諸問題を解決し、わが国をはじめとした高齢化社会に有利な環境を作りだせる一つの手がかりとなることが期待される。(著者抄録)

researchmap

Language：Japanese   Publisher：(一社)日本老年医学会  

DOI： 10.3143/geriatrics.46.117

researchmap

Language：Japanese   Publisher：(株)協和企画  

5歳女。出生時より両手指の爪の変形に気付いていた。受診時、拇指爪の形成不全、示指の縦走隆起、環指の三角状爪半月、小指爪に中央を縦走する溝を認め、膝蓋骨の低形成、腸骨の角状突起も認めた。また、末梢白血球より抽出したゲノムDNAを用い、PCR-ダイレクトシークエンス法でLMX1B遺伝子の偏位解析を行ったところ、exon3においてc.368-369de1TG(p.C123X)のナンセンス変異をヘテロに見出した。Nail-patella症候群と診断し、父親の遺伝子解析でも同様の変異をヘテロに認めた。手指の爪、膝については定期的に経過観察を行い、年に1、2回の尿検査で腎症状のチェックを行っている。一時的に眼圧が上昇したためトラバタンズを使用していたが正常化し、現在経過観察中である。

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

疾患で侵された骨・関節の機能回復のための外科治療技術が発達してきた。骨関節領域では材料工学、生体工学技術を背景にした種々の人工関節や人工骨の発展と普及によって、多くの患者の失われた運動機能が回復可能となり、QOL(quality of life)の維持回復に大きな福音となっている。一方で、骨関節でも基礎医学としての再生医学の発達も徐々にではあるが発展しつつある。しかし、実地臨床への利用やその普及という面ではまだまだ大きく研究の余地が残されているのが現状であろう。従って、臨床の場での骨再生にあたっては、いまだに古典的な自家骨移植に頼っている。自家骨移植では血管柄付骨移植や生体材料との複合などの工夫はあるが、採骨部の障害、採骨量の限界などでその効果は限定的と問わざるを得ない。それゆえ、巨大骨欠損の再生修復には、現在でも大きな困難が伴っている。飛躍的な骨再生技術の開発においては、このような現状を打開し、骨再生に必須である局所的骨形成を誘発する先進的な技術開発が待たれている。そのような技術として、局所的に骨形成を誘発する活性を有している骨形成因子(bone morphogenetic protein:BMP)を有効利用することが有望である。(著者抄録)

researchmap

Language：Japanese   Publisher：金原出版(株)  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：(一社)日本骨代謝学会  

researchmap

Language：Japanese   Publisher：(株)医学書院  

小児股関節疾患のうち,重症ペルテス病,大腿骨頭すべり症後や大腿骨頸部骨折後の大腿骨頭壊死などの変形を遺残しうる思春期大腿骨壊死性疾患に対する大腿骨頭回転骨切り術を,術前CTデータから作成した造型モデルを用いてシミュレーションした.すなわち,寛骨臼との良好な適合性を保ちつつ,壊死を免れた荷重に耐える骨頭部分を荷重部に移動する最適な方向と角度を術前に求め,手術施行の支援とした.対象とした7股中5股において骨頭後方回転骨切り術のほうが前方回転骨切り術よりも良好な臼蓋-健常骨頭適合性が得られることが判明した.(著者抄録)

DOI： 10.11477/mf.1408101377

researchmap

Language：Japanese   Publisher：(有)科学評論社  

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

今まで閉経後骨粗鬆症の分子基盤は明らかではなかった。今回のわれわれの研究結果から、女性ホルモン(エストロゲン)は骨吸収を担う破骨細胞におけるエストロゲン受容体αを介し、破骨細胞でのFas ligandの発現を上昇させることで破骨細胞のアポトーシスを誘導し、骨吸収を制御することにより骨量を維持していることを明らかにすることができた。(著者抄録)

researchmap

Language：Japanese   Publisher：(有)科学評論社  

researchmap

Language：Japanese   Publisher：(株)医薬ジャーナル社  

骨の強さは、骨組織に対する適切な荷重により維持されており、また骨組織自体がメカニカルストレスを感知・受容していることは明らかである。しかしながら、骨組織を構成する細胞群におけるメカニカルストレス伝達機構の詳細な分子基盤の大部分は依然として不明なままであるが、近年、エストロゲン受容体α(ERα)が骨細胞寿命の調節や骨芽細胞などでのメカニカルストレス伝達機構において重要な役割を果たしていることが明らかとなってきた。ERαの細胞内でのさらなる詳細な機能メカニズムの解明は非常に興味深い。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)南江堂  

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

エストロゲン欠乏によって引き起こされる閉経後骨粗鬆症は先進諸国において広範に認められる疾患である。ヒトやマウスにおけるエストロゲンの骨防御作用についてはよく知られているが、1992年に作出された女性ホルモン受容体(ER)欠損マウスの研究により、閉経後骨粗鬆症の分子レベルでの定義が大きく変化する可能性が出てきた。ERαおよびERβ遺伝子欠損マウスでは、卵巣摘出によるエストロゲン欠乏状態のマウス系統にみられる明確な骨量減少は認められなかった。我々は、破骨細胞特異的ERα遺伝子欠損マウスを作製することによって、エストロゲンの骨防御作用における破骨細胞特異的なERαの生理作用について説明した。我々は、破骨細胞特異的発現遺伝子であるCathepsin K遺伝子をCre遺伝子に置き換えたマウス系統の樹立を行った。次に、ERα遺伝子座にloxP配列をもつERα floxedマウスとの交配により破骨細胞特異的ERα遺伝子欠損マウスを作出した。その結果、雌の破骨細胞特異的ERα遺伝子欠損マウスにのみ大腿骨遠位部および脊椎骨における海綿骨量の減少、さらに破骨細胞数の増加に伴う高回転型の骨粗鬆症が認められた。そこで、活性型女性ホルモンの投与により破骨細胞内で変動する遺伝子発現をDNAマイクロアレイにより検索したところ、ERα標的遺伝子としてFasリガンドが特定された。これらの研究結果より、成熟破骨細胞の寿命は女性ホルモンによって誘導されるアポトーシス誘導因子Fasリガンドによって規定されていることが明らかになった。エストロゲンの骨吸収抑制作用による骨防御作用は成熟破骨細胞の正常な寿命の維持であると推定された。(著者抄録)

researchmap

Language：Japanese   Publisher：(株)メディカルレビュー社  

researchmap

Language：Japanese   Publisher：金原出版(株)  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：ELSEVIER SCIENCE INC  

DOI： 10.1016/j.bone.2007.12.058

Web of Science

researchmap

Language：Japanese   Publisher：日本小児整形外科学会  

当院で感染に対する初期治療を行った小児化膿性股関節炎の症例について、その治療経過と経過観察例の予後について検討した。対象は1994年6月〜2006年6月の11例で発症時年齢は1ヵ月未満が5例、起炎菌はMSSAが2例、MRSAが4例、PRSPが1例、その他2例、陰性2例で血液培養ではMRSAの4例のみ菌が検出された。治療は1例で穿刺による排膿、洗浄を行い、他はすべて最終的に切開排膿を行い同時に抗菌剤の点滴静注を行った。MRSA例は全て1ヵ月未満の新生児で敗血症を呈しており、多発性の関節炎、骨髄炎をきたしている例もあり全例骨頭、頸部に変形を認め脚長不等をきたした。MRSA以外で経過観察できた症例では軽度のcoxa magnaを認める以外経過良好であった。新生児の化膿性股関節炎例では早期診断、治療につとめる必要があり、また多剤耐性菌を念頭において治療を行う必要がある。(著者抄録)

researchmap

Language：Japanese   Publishing type：Book review, literature introduction, etc.  

Bone mass and strength is mediated by appropriate weight bearing, and it is clear that bone tissue senses and adopts mechanical stresses. However, the precise molecular mechanisms in mechanotransduction remain elusive. Recently, several studies clarified that estrogen receptor alpha (ERalpha) plays important role in mechanotransduction. For example, the lifespan of osteocytes is prolonged by mechanical loading through ERalpha action, which is produced by the plentiful expression of ERalpha in osteocytes. Although these recent findings clearly show the important role of ERalpha in mechanotransduction, the intracellular function of ERalpha is still largely unknown. In this point of view, it will be a great interest to elucidate how ERs functionally associate with regulators involved with mechanotransductions in bone cells.

Scopus

PubMed

researchmap

Language：Japanese   Publishing type：Book review, literature introduction, etc.  

Treatments for locomotive organs, such as bone and joint, have been investigated and preceded in recent decades. Especially, in orthopaedic field, therapeutic alternatives for total joint arthroplasty for osteoarthritis and spinal fusion have remarkably advanced. However, bone regeneration required in massive bone defect or broad spinal fusion have been treated with bone graft mainly using auto grafted bone here in Japan. These methods have several issues such as limited bone regeneration or pain in harvest sites. We would like to describe perspectives and biology in bone regeneration focusing on bone morphogenetic protein (BMP).

Scopus

PubMed

researchmap

Language：Japanese   Publisher：(株)学研メディカル秀潤社  

researchmap

Language：Japanese   Publisher：(株)南江堂  

researchmap

Language：English   Publishing type：Research paper, summary (international conference)   Publisher：AMER SOC BONE & MINERAL RES  

Web of Science

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：日本小児整形外科学会  

先天性筋性斜頸は自然軽快することの多い疾患であるが、稀に観血的治療を要する症例も存在するため身体所見およびその評価方法が重要である。斜頸に伴って生じる身体所見の一つとして顔面非対称性が挙げられるが、その客観的評価は難しい。我々は外来でのインスタント写真を用いて顔面非対称性を評価している。一般的に顔面非対称性が2歳までに徐々に減少する症例では手術に至らない症例が多く、変化なし、または徐々に増加する症例では手術に至る症例が多いことが示唆される。2歳を過ぎても胸鎖乳突筋部の拘縮、頸部可動域制限、顔面非対称性を認める場合に、胸鎖乳突筋下端切除術を行っている。術後はおおむね顔面非対称性は徐々に減少する結果を示したが、手術時年齢6歳、術後1年強の1例で顔面非対称性を残している。年長になってからの先天性筋性斜頸手術では顔面非対称性の完全な回復が難しく、筋性斜頸の手術治療については適応に年齢の制限はないが、顔面非対称性を残存させないためには5歳までの手術が望ましいと考えられる。(著者抄録)

researchmap

Language：Japanese   Publisher：(一社)日本手外科学会  

マウス生体爪再生モデルを用いて、爪組織再生過程における分子制機構を明らかにし、爪の再生に重要な役割を担う分子の同定を行った。6週齢ICRマウスの前肢中指の抜爪後の経時的組織学的検索では抜爪後3日目で爪甲の再生が観察され、21日目には再生がほぼ完成していた。in situ hybridizationを用いた遺伝子局在の検索では、爪の再生過程においてMsx1およびHoxc13のmRNAは主に爪母細胞に発現しており、抜爪後3日目に上昇する発現パターンを示しMsx1、Hoxc13、mRNAの発現亢進が確認されたことより、これらの遺伝子が爪の発生に重要な役割を担っていることが示唆された。転写因子発現調節にかかわる可能性があるBMP4も同様の発現パターンを示したことより、組織損傷後の爪再生過程にはBMPも関与している可能性が考えられた。

researchmap

Language：Japanese  

CiNii Books

researchmap

Language：Japanese   Publisher：(株)日本医学館  

再生医学技術の基礎研究はめざましい進歩を遂げ,一部が先端的医療として臨床応用されはじめている.骨組織における再生医療も同様な傾向にある.一般に,分化組織再生という生物現象には3要素が必須であるとされる. 1)多分化能を有する未分化細胞, 2)細胞の増殖・分化を制御する成長因子/サイトカイン, 3)細胞が増殖・分化する足場(scaffold)である.未分化間葉系細胞を特異的に軟骨細胞または骨芽細胞へ分化誘導し,骨誘導活性を発揮するbon morphogenetic protein(BMP)が種々の動物で骨組織再生を可能にすることが確かめられている.BMP familyの一分子が単一で,間葉系細胞に作用してin vivoで骨新生を可能にすることは骨再生においてはきわめて重要であるが,ヒトでの臨床利用に広く用いるには,いまだ解決すべき問題点が残されている.それらの主要な問題点は,有効で安全性の高いDDSの開発,ヒトでのBMPに対する低い応答性などである.これらの問題解決によって汎用性が高い画期的な骨再生・骨修復技術となることが期待できる(著者抄録)

researchmap

Language：Japanese   Publisher：日本小児整形外科学会  

researchmap

Language：Japanese   Publisher：日本小児整形外科学会  

researchmap

Language：Japanese   Publisher：近畿小児整形外科懇話会  

運動時股関節痛を訴えた2例(症例1:14歳男児,症例2:15歳女児)に対し,離断性骨軟骨炎(OCD)の合併を疑い,MR Arthrography及び股関節鏡を施行した.症例1のMR Arthrographyでは骨頭頂部付近の荷重面に一致して等信号領域に囲まれた低信号領域を認めたためOCDと診断し,股関節鏡を行なったところ同部位に大腿骨頭の関節軟骨にSofteningを認めた.症例2ではMR Arthrographyで大腿骨頭頂部に一部周囲との連続性を保った高信号領域に囲まれた低信号領域を,関節包内後方下部の2ヶ所に高信号領域に囲まれた低信号領域を認めた.股関節鏡では大腿骨頭頂部,円靱帯付近部近傍に遊離しかけたOsteochondral fragmentを認めた.しかし,遊離体は確認不能であり,関節切開に変更し遊離体を2つ確認した.以上の股関節鏡所見から,MR Arthorgramにおいて,等信号領域(造影効果を受けた軟骨組織)で隔絶された低信号領域を認めた場合は大腿骨頭と連続性のある軟骨組織に覆われたOCDである可能性が高く,又,高信号領域(造影剤で隔絶された低信号領域)を認めた場合は遊離体が存在している可能性が高いと考えられた

researchmap